<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2020-07-29T18:48:50.7103179+00:00 -->
<!-- Version            : 5.0.1.476 -->
<!-- Package ID         : 457a28045a8a4945a4a6e6eb3bfeab6d -->
<!-- Copyright (c) 2020 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <link:roleRef xlink:type="simple" xlink:href="bro-20200630.xsd#TemplateLink" roleURI="http://www.bbinsurance.com/20200630/role/TemplateLink" />
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFEQUITYUNAUDITED" xlink:href="bro-20200630.xsd#Role_StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFEQUITYUNAUDITED" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/StatementCONDENSEDCONSOLIDATEDSTATEMENTSOFEQUITYUNAUDITED">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsCash" xlink:type="locator" xlink:label="us-gaap_DividendsCash" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueIssuedForServices" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:type="locator" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesAcquisitions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueAcquisitions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan" />
    <link:loc xlink:href="bro-20200630.xsd#bro_StockIssuedDuringPeriodValueEmployeeBenefitPlanNetOfForfeitures" xlink:type="locator" xlink:label="bro_StockIssuedDuringPeriodValueEmployeeBenefitPlanNetOfForfeitures" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesOutstanding" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity" xlink:type="locator" xlink:label="us-gaap_StockholdersEquity" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember" xlink:type="locator" xlink:label="us-gaap_TreasuryStockMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AdditionalPaidInCapitalMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_TreasuryStockMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_RetainedEarningsMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquity" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CommonStockSharesOutstanding" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLoss" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="bro_StockIssuedDuringPeriodValueEmployeeBenefitPlanNetOfForfeitures" order="10620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeBenefitPlan" order="10640.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueAcquisitions" order="10760.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesAcquisitions" order="10780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_TreasuryStockValueAcquiredCostMethod" order="10900.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueIssuedForServices" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" order="11060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_DividendsCash" order="11180.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBasisOfFinancialReportingAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureBasisOfFinancialReportingAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBasisOfFinancialReportingAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:type="locator" xlink:label="us-gaap_AssetImpairmentCharges" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountingStandardsUpdate201704Member" xlink:type="locator" xlink:label="us-gaap_AccountingStandardsUpdate201704Member" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:type="locator" xlink:label="us-gaap_TypeOfAdoptionMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:type="locator" xlink:label="us-gaap_TypeOfAdoptionMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:type="locator" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:type="locator" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:to="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:to="us-gaap_TypeOfAdoptionMember" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TypeOfAdoptionMember" xlink:to="us-gaap_AccountingStandardsUpdate201704Member" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:to="us-gaap_AssetImpairmentCharges" order="10120.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureRevenuesScheduleOfDisaggregatedByRevenueDetails" xlink:href="bro-20200630.xsd#Role_DisclosureRevenuesScheduleOfDisaggregatedByRevenueDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureRevenuesScheduleOfDisaggregatedByRevenueDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:type="locator" xlink:label="us-gaap_Revenues" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherIncome" xlink:type="locator" xlink:label="us-gaap_OtherIncome" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentIncomeNonoperating" xlink:type="locator" xlink:label="us-gaap_InvestmentIncomeNonoperating" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="locator" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:type="locator" xlink:label="us-gaap_OperatingSegmentsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateNonSegmentMember" xlink:type="locator" xlink:label="us-gaap_CorporateNonSegmentMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain" xlink:type="locator" xlink:label="srt_ConsolidationItemsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain" xlink:type="locator" xlink:label="srt_ConsolidationItemsDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis" xlink:type="locator" xlink:label="srt_ConsolidationItemsAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ServicesMember" xlink:type="locator" xlink:label="bro_ServicesMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WholesaleBrokerageMember" xlink:type="locator" xlink:label="bro_WholesaleBrokerageMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NationalProgramsMember" xlink:type="locator" xlink:label="bro_NationalProgramsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetailMember" xlink:type="locator" xlink:label="us-gaap_RetailMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_GuaranteedSupplementalCommissionRevenueMember" xlink:type="locator" xlink:label="bro_GuaranteedSupplementalCommissionRevenueMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ProfitSharingContingentCommissionRevenueMember" xlink:type="locator" xlink:label="bro_ProfitSharingContingentCommissionRevenueMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_IncentiveCommissionRevenueMember" xlink:type="locator" xlink:label="bro_IncentiveCommissionRevenueMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FeeRevenueMember" xlink:type="locator" xlink:label="bro_FeeRevenueMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_CoreCommissionRevenueMember" xlink:type="locator" xlink:label="bro_CoreCommissionRevenueMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:type="locator" xlink:label="srt_ProductsAndServicesDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:type="locator" xlink:label="srt_ProductOrServiceAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:type="locator" xlink:label="us-gaap_DisaggregationOfRevenueLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_DisaggregationOfRevenueTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="srt_ProductOrServiceAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductsAndServicesDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="bro_CoreCommissionRevenueMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="bro_FeeRevenueMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="bro_IncentiveCommissionRevenueMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="bro_ProfitSharingContingentCommissionRevenueMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ProductsAndServicesDomain" xlink:to="bro_GuaranteedSupplementalCommissionRevenueMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain_2" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_RetailMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_NationalProgramsMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_WholesaleBrokerageMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_ServicesMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DisaggregationOfRevenueTable" xlink:to="srt_ConsolidationItemsAxis" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_ConsolidationItemsAxis" xlink:to="srt_ConsolidationItemsDomain_2" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidationItemsAxis" xlink:to="srt_ConsolidationItemsDomain" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidationItemsDomain" xlink:to="us-gaap_CorporateNonSegmentMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidationItemsDomain" xlink:to="us-gaap_OperatingSegmentsMember" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" order="12980.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_InvestmentIncomeNonoperating" order="13580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_OtherIncome" order="13700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DisaggregationOfRevenueLineItems" xlink:to="us-gaap_Revenues" order="13820.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureRevenuesAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureRevenuesAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureRevenuesAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:type="locator" xlink:label="us-gaap_CapitalizedContractCostAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredCostsCurrentAndNoncurrent" xlink:type="locator" xlink:label="us-gaap_DeferredCostsCurrentAndNoncurrent" />
    <link:loc xlink:href="bro-20200630.xsd#bro_OffsetOfRevisedEstimatedVariableConsideration" xlink:type="locator" xlink:label="bro_OffsetOfRevisedEstimatedVariableConsideration" />
    <link:loc xlink:href="bro-20200630.xsd#bro_VariableConsiderationReceived" xlink:type="locator" xlink:label="bro_VariableConsiderationReceived" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent" />
    <link:loc xlink:href="bro-20200630.xsd#bro_CosttoFulfillMember" xlink:type="locator" xlink:label="bro_CosttoFulfillMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_CosttoObtainMember" xlink:type="locator" xlink:label="bro_CosttoObtainMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterimPeriodCostsNotAllocableDomain" xlink:type="locator" xlink:label="us-gaap_InterimPeriodCostsNotAllocableDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterimPeriodCostsNotAllocableDomain" xlink:type="locator" xlink:label="us-gaap_InterimPeriodCostsNotAllocableDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NatureOfExpenseAxis" xlink:type="locator" xlink:label="us-gaap_NatureOfExpenseAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_NatureOfExpenseAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_NatureOfExpenseAxis" xlink:to="us-gaap_InterimPeriodCostsNotAllocableDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_NatureOfExpenseAxis" xlink:to="us-gaap_InterimPeriodCostsNotAllocableDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InterimPeriodCostsNotAllocableDomain" xlink:to="bro_CosttoObtainMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InterimPeriodCostsNotAllocableDomain" xlink:to="bro_CosttoFulfillMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ContractWithCustomerLiabilityNoncurrent" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ContractWithCustomerLiabilityRevenueRecognized" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="bro_VariableConsiderationReceived" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="bro_OffsetOfRevisedEstimatedVariableConsideration" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_DeferredCostsCurrentAndNoncurrent" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_CapitalizedContractCostAmortization" order="10500.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureBusinessCombinationsAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsAdditionalInformationDetails">
    <link:loc xlink:href="bro-20200630.xsd#bro_ExpectedPaymentPeriodOfEarnOutPayments" xlink:type="locator" xlink:label="bro_ExpectedPaymentPeriodOfEarnOutPayments" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ExpectedMaximumDeemedEarnOutPayments" xlink:type="locator" xlink:label="bro_ExpectedMaximumDeemedEarnOutPayments" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ExpectedMinimumCalculatedEarnOutPayments" xlink:type="locator" xlink:label="bro_ExpectedMinimumCalculatedEarnOutPayments" />
    <link:loc xlink:href="bro-20200630.xsd#bro_MaximumFutureContingencyPaymentsAcquisitions" xlink:type="locator" xlink:label="bro_MaximumFutureContingencyPaymentsAcquisitions" />
    <link:loc xlink:href="bro-20200630.xsd#bro_BusinessAcquisitionEarnOutPayables" xlink:type="locator" xlink:label="bro_BusinessAcquisitionEarnOutPayables" />
    <link:loc xlink:href="bro-20200630.xsd#bro_BusinessCombinationProFormaInformationIncomeLossBeforeIncomeTaxesOfAcquireeSinceAcquisitionDateActual" xlink:type="locator" xlink:label="bro_BusinessCombinationProFormaInformationIncomeLossBeforeIncomeTaxesOfAcquireeSinceAcquisitionDateActual" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" />
    <link:loc xlink:href="bro-20200630.xsd#bro_EarnOutPayableNotDeductibleUntilEarnedPaid" xlink:type="locator" xlink:label="bro_EarnOutPayableNotDeductibleUntilEarnedPaid" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" />
    <link:loc xlink:href="bro-20200630.xsd#bro_GoodwillAcquiredDuringPeriodAdjustedAmount" xlink:type="locator" xlink:label="bro_GoodwillAcquiredDuringPeriodAdjustedAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:type="locator" xlink:label="us-gaap_GoodwillAcquiredDuringPeriod" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:type="locator" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross" />
    <link:loc xlink:href="bro-20200630.xsd#bro_BusinessAcquisitionsPurchasePriceAllocationAdjustmentPurchasePrice" xlink:type="locator" xlink:label="bro_BusinessAcquisitionsPurchasePriceAllocationAdjustmentPurchasePrice" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfBusinessesAcquired" xlink:type="locator" xlink:label="us-gaap_NumberOfBusinessesAcquired" />
    <link:loc xlink:href="bro-20200630.xsd#bro_AssetPurchaseAgreementMember" xlink:type="locator" xlink:label="bro_AssetPurchaseAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:type="locator" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:type="locator" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:type="locator" xlink:label="us-gaap_TypeOfArrangementAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentLiabilitiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableMember" xlink:type="locator" xlink:label="us-gaap_AccountsPayableMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_ExtinguishmentOfDebtTypeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_ExtinguishmentOfDebtTypeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ExtinguishmentOfDebtAxis" xlink:type="locator" xlink:label="us-gaap_ExtinguishmentOfDebtAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ServicesMember" xlink:type="locator" xlink:label="bro_ServicesMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WholesaleBrokerageMember" xlink:type="locator" xlink:label="bro_WholesaleBrokerageMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NationalProgramsMember" xlink:type="locator" xlink:label="bro_NationalProgramsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetailMember" xlink:type="locator" xlink:label="us-gaap_RetailMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:type="locator" xlink:label="us-gaap_NoncompeteAgreementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_OtherAcquisitionsMember" xlink:type="locator" xlink:label="bro_OtherAcquisitionsMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_BookOfBusinessPurchaseMember" xlink:type="locator" xlink:label="bro_BookOfBusinessPurchaseMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_AssetsAcquisitionsAndBookOfBusinessPurchasesMember" xlink:type="locator" xlink:label="bro_AssetsAcquisitionsAndBookOfBusinessPurchasesMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_AssetAcquisitionsMember" xlink:type="locator" xlink:label="bro_AssetAcquisitionsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_AssetAcquisitionsMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_AssetsAcquisitionsAndBookOfBusinessPurchasesMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_BookOfBusinessPurchaseMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_OtherAcquisitionsMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="srt_RangeAxis" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember_2" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10310.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerRelationshipsMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_NoncompeteAgreementsMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="10360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_RetailMember" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_NationalProgramsMember" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_WholesaleBrokerageMember" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_ServicesMember" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_ExtinguishmentOfDebtAxis" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ExtinguishmentOfDebtAxis" xlink:to="us-gaap_ExtinguishmentOfDebtTypeDomain_2" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ExtinguishmentOfDebtAxis" xlink:to="us-gaap_ExtinguishmentOfDebtTypeDomain" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ExtinguishmentOfDebtTypeDomain" xlink:to="us-gaap_AccountsPayableMember" order="10530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="10540.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain_2" order="10550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentLiabilitiesMember" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_TypeOfArrangementAxis" order="10600.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TypeOfArrangementAxis" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_2" order="10610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:to="bro_AssetPurchaseAgreementMember" order="10650.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_NumberOfBusinessesAcquired" order="10740.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_BusinessAcquisitionsPurchasePriceAllocationAdjustmentPurchasePrice" order="10830.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross" order="10880.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="10990.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_GoodwillAcquiredDuringPeriod" order="11110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_GoodwillAcquiredDuringPeriodAdjustedAmount" order="11190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" order="11230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_EarnOutPayableNotDeductibleUntilEarnedPaid" order="11250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" order="11300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_BusinessCombinationProFormaInformationIncomeLossBeforeIncomeTaxesOfAcquireeSinceAcquisitionDateActual" order="11320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_BusinessAcquisitionEarnOutPayables" order="11370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_MaximumFutureContingencyPaymentsAcquisitions" order="11430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_ExpectedMinimumCalculatedEarnOutPayments" order="11500.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_ExpectedMaximumDeemedEarnOutPayments" order="11520.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="bro_ExpectedPaymentPeriodOfEarnOutPayments" order="11540.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsPurchasePriceAllocationForCurrentYearAcquisitionsAndAdjustmentsMadeForPriorYearAcquisitionsDetails" xlink:href="bro-20200630.xsd#Role_DisclosureBusinessCombinationsPurchasePriceAllocationForCurrentYearAcquisitionsAndAdjustmentsMadeForPriorYearAcquisitionsDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsPurchasePriceAllocationForCurrentYearAcquisitionsAndAdjustmentsMadeForPriorYearAcquisitionsDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueAcquisitions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" />
    <link:loc xlink:href="bro-20200630.xsd#bro_VariousMember" xlink:type="locator" xlink:label="bro_VariousMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetailMember" xlink:type="locator" xlink:label="us-gaap_RetailMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WholesaleBrokerageMember" xlink:type="locator" xlink:label="bro_WholesaleBrokerageMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NationalProgramsMember" xlink:type="locator" xlink:label="bro_NationalProgramsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_OtherAcquisitionsMember" xlink:type="locator" xlink:label="bro_OtherAcquisitionsMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_LPInsuranceServicesLimitedLiabilityCompanyMember" xlink:type="locator" xlink:label="bro_LPInsuranceServicesLimitedLiabilityCompanyMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" xlink:type="locator" xlink:label="bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_RLAInsuranceIntermediariesLLCMember" xlink:type="locator" xlink:label="bro_RLAInsuranceIntermediariesLLCMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ColonialGroupIncMember" xlink:type="locator" xlink:label="bro_ColonialGroupIncMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_TexasAllRiskGeneralAgencyIncMember" xlink:type="locator" xlink:label="bro_TexasAllRiskGeneralAgencyIncMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_SpecialRiskInsuranceManagersLtdMember" xlink:type="locator" xlink:label="bro_SpecialRiskInsuranceManagersLtdMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsTable" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_SpecialRiskInsuranceManagersLtdMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_TexasAllRiskGeneralAgencyIncMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_ColonialGroupIncMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_RLAInsuranceIntermediariesLLCMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_LPInsuranceServicesLimitedLiabilityCompanyMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_OtherAcquisitionsMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_NationalProgramsMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_WholesaleBrokerageMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_RetailMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_VariousMember" order="10390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross" order="10620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueAcquisitions" order="10820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred" order="11020.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" order="11220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="11420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsLineItems" xlink:to="us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh" order="11620.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsEstimatedFairValuesOfAggregateAssetsAndLiabilitiesAcquiredDetails" xlink:href="bro-20200630.xsd#Role_DisclosureBusinessCombinationsEstimatedFairValuesOfAggregateAssetsAndLiabilitiesAcquiredDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureBusinessCombinationsEstimatedFairValuesOfAggregateAssetsAndLiabilitiesAcquiredDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillFairValueDisclosure" xlink:type="locator" xlink:label="us-gaap_GoodwillFairValueDisclosure" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" />
    <link:loc xlink:href="bro-20200630.xsd#bro_BusinessAcquisitionsPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents" xlink:type="locator" xlink:label="bro_BusinessAcquisitionsPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents" />
    <link:loc xlink:href="bro-20200630.xsd#bro_OtherAcquisitionAdjustmentsMember" xlink:type="locator" xlink:label="bro_OtherAcquisitionAdjustmentsMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_LPInsuranceServicesLimitedLiabilityCompanyMember" xlink:type="locator" xlink:label="bro_LPInsuranceServicesLimitedLiabilityCompanyMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" xlink:type="locator" xlink:label="bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_RLAInsuranceIntermediariesLLCMember" xlink:type="locator" xlink:label="bro_RLAInsuranceIntermediariesLLCMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ColonialGroupIncMember" xlink:type="locator" xlink:label="bro_ColonialGroupIncMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_TexasAllRiskGeneralAgencyIncMember" xlink:type="locator" xlink:label="bro_TexasAllRiskGeneralAgencyIncMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_SpecialRiskAcquisitionAdjustmentsMember" xlink:type="locator" xlink:label="bro_SpecialRiskAcquisitionAdjustmentsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:type="locator" xlink:label="us-gaap_NoncompeteAgreementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerListsMember" xlink:type="locator" xlink:label="us-gaap_CustomerListsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FairValueOfAssetsAndLiabilitiesStatementTable" xlink:type="locator" xlink:label="bro_FairValueOfAssetsAndLiabilitiesStatementTable" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:type="locator" xlink:label="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="bro_FairValueOfAssetsAndLiabilitiesStatementTable" order="10120.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerListsMember" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_NoncompeteAgreementsMember" order="10220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_SpecialRiskAcquisitionAdjustmentsMember" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_TexasAllRiskGeneralAgencyIncMember" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_ColonialGroupIncMember" order="10320.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_RLAInsuranceIntermediariesLLCMember" order="10340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_DealerFinancialServicesOfNCLimitedLiabilityCompanyMember" order="10360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_LPInsuranceServicesLimitedLiabilityCompanyMember" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="bro_OtherAcquisitionAdjustmentsMember" order="10400.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="bro_BusinessAcquisitionsPurchasePriceAllocationCurrentAssetsCashAndCashEquivalents" order="10430.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_GoodwillFairValueDisclosure" order="10910.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" order="11070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" order="11390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" order="11550.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther" order="11710.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" order="11870.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" order="12030.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="bro_FairValueOfAssetsAndLiabilitiesStatementLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" order="12190.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureGoodwillChangesInCarryingValueOfGoodwillByOperatingSegmentDetails" xlink:href="bro-20200630.xsd#Role_DisclosureGoodwillChangesInCarryingValueOfGoodwillByOperatingSegmentDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureGoodwillChangesInCarryingValueOfGoodwillByOperatingSegmentDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" xlink:type="locator" xlink:label="us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:type="locator" xlink:label="us-gaap_GoodwillAcquiredDuringPeriod" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ServicesMember" xlink:type="locator" xlink:label="bro_ServicesMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WholesaleBrokerageMember" xlink:type="locator" xlink:label="bro_WholesaleBrokerageMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NationalProgramsMember" xlink:type="locator" xlink:label="bro_NationalProgramsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetailMember" xlink:type="locator" xlink:label="us-gaap_RetailMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfGoodwillTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillLineItems" xlink:type="locator" xlink:label="us-gaap_GoodwillLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_ScheduleOfGoodwillTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfGoodwillTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_RetailMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_NationalProgramsMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_WholesaleBrokerageMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_ServicesMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_Goodwill" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_GoodwillAcquiredDuringPeriod" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_GoodwillLineItems" xlink:to="us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit" order="10420.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureAmortizableIntangibleAssetsAmortizableIntangibleAssetsDetails" xlink:href="bro-20200630.xsd#Role_DisclosureAmortizableIntangibleAssetsAmortizableIntangibleAssetsDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureAmortizableIntangibleAssetsAmortizableIntangibleAssetsDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncompeteAgreementsMember" xlink:type="locator" xlink:label="us-gaap_NoncompeteAgreementsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10060.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerRelationshipsMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_NoncompeteAgreementsMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" order="10260.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill" order="10360.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetUsefulLife" order="10460.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtScheduleOfLongTermDebtDetails" xlink:href="bro-20200630.xsd#Role_DisclosureLongTermDebtScheduleOfLongTermDebtDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtScheduleOfLongTermDebtDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt" xlink:type="locator" xlink:label="us-gaap_LongTermDebt" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:type="locator" xlink:label="us-gaap_LongTermDebtCurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:type="locator" xlink:label="us-gaap_LongTermDebtNoncurrent" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsGross" xlink:type="locator" xlink:label="us-gaap_DeferredFinanceCostsGross" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermLineOfCredit" xlink:type="locator" xlink:label="us-gaap_LongTermLineOfCredit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeniorLongTermNotes" xlink:type="locator" xlink:label="us-gaap_SeniorLongTermNotes" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LinesOfCreditCurrent" xlink:type="locator" xlink:label="us-gaap_LinesOfCreditCurrent" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" xlink:type="locator" xlink:label="bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" xlink:type="locator" xlink:label="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" xlink:type="locator" xlink:label="bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" xlink:type="locator" xlink:label="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" xlink:type="locator" xlink:label="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10060.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentAxis" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain_2" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" order="10200.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" order="10240.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LinesOfCreditCurrent" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_SeniorLongTermNotes" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermLineOfCredit" order="10530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DeferredFinanceCostsGross" order="10690.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtNoncurrent" order="10730.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtCurrent" order="10770.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebt" order="10810.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtScheduleOfLongTermDebtParentheticalDetails" xlink:href="bro-20200630.xsd#Role_DisclosureLongTermDebtScheduleOfLongTermDebtParentheticalDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtScheduleOfLongTermDebtParentheticalDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeePercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationPeriod" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityExpirationPeriod" />
    <link:loc xlink:href="bro-20200630.xsd#bro_DebtInstrumentsMaturityYear" xlink:type="locator" xlink:label="bro_DebtInstrumentsMaturityYear" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:type="locator" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis" xlink:type="locator" xlink:label="us-gaap_VariableRateAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" xlink:type="locator" xlink:label="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" xlink:type="locator" xlink:label="bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" xlink:type="locator" xlink:label="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" xlink:type="locator" xlink:label="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" xlink:type="locator" xlink:label="bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FourPointTwoZeroZeroPercentSeniorNotesDueTwoThousandTwentyFourMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyTwoMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearRevolvingLoanFacilityExpiresInTwoThousandTwentyTwoMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FiveYearTermLoanFacilityExpiresInTwoThousandTwentyThreeMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="srt_RangeAxis" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_VariableRateAxis" order="10580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain_2" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain" order="10610.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember" order="10630.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage" order="10700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="bro_DebtInstrumentsMaturityYear" order="10780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityExpirationPeriod" order="10860.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityExpirationDate1" order="10980.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" order="11100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityCommitmentFeePercentage" order="11220.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureLongTermDebtAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLongTermDebtAdditionalInformationDetails">
    <link:loc xlink:href="bro-20200630.xsd#bro_AdjustedLiborRate" xlink:type="locator" xlink:label="bro_AdjustedLiborRate" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SeniorNotes" xlink:type="locator" xlink:label="us-gaap_SeniorNotes" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentPeriodicPayment" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentPeriodicPayment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" />
    <link:loc xlink:href="bro-20200630.xsd#bro_DebtInstrumentRepaymentTerm" xlink:type="locator" xlink:label="bro_DebtInstrumentRepaymentTerm" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt" xlink:type="locator" xlink:label="us-gaap_LongTermDebt" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCredit" xlink:type="locator" xlink:label="us-gaap_LineOfCredit" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFaceAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnsecuredLongTermDebt" xlink:type="locator" xlink:label="us-gaap_UnsecuredLongTermDebt" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:type="locator" xlink:label="us-gaap_DeferredFinanceCostsNoncurrentNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:type="locator" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentPrincipal" />
    <link:loc xlink:href="bro-20200630.xsd#bro_UnsecuredRevolvingCreditFacility" xlink:type="locator" xlink:label="bro_UnsecuredRevolvingCreditFacility" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:type="locator" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis" xlink:type="locator" xlink:label="us-gaap_VariableRateAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtMember" xlink:type="locator" xlink:label="us-gaap_LongTermDebtMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" xlink:type="locator" xlink:label="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_UnsecuredSeniorNotesMember" xlink:type="locator" xlink:label="bro_UnsecuredSeniorNotesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_TermLoanMember" xlink:type="locator" xlink:label="bro_TermLoanMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="bro_TermLoanMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_UnsecuredSeniorNotesMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_RevolvingCreditFacilityMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="srt_RangeAxis" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10470.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="bro_FourPointFiveZeroZeroPercentSeniorNotesDueTwoThousandTwentyNineMember" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_LongTermDebtMember" order="10750.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_VariableRateAxis" order="10760.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain" order="10790.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember" order="10810.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="bro_UnsecuredRevolvingCreditFacility" order="10840.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentPeriodicPaymentPrincipal" order="10920.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_ProceedsFromIssuanceOfDebt" order="10960.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_WriteOffOfDeferredDebtIssuanceCost" order="11000.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DeferredFinanceCostsNoncurrentNet" order="11040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_UnsecuredLongTermDebt" order="11080.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentFaceAmount" order="11270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage" order="11330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCredit" order="11390.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebt" order="11450.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="bro_DebtInstrumentRepaymentTerm" order="11620.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" order="11660.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentPeriodicPayment" order="11780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_SeniorNotes" order="11930.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="bro_AdjustedLiborRate" order="12200.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLeasesAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureLeasesAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureLeasesAdditionalInformationDetails">
    <link:loc xlink:href="bro-20200630.xsd#bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesDueInYearTwo" xlink:type="locator" xlink:label="bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesDueInYearTwo" />
    <link:loc xlink:href="bro-20200630.xsd#bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesRemainderOfFiscalYear" xlink:type="locator" xlink:label="bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesRemainderOfFiscalYear" />
    <link:loc xlink:href="bro-20200630.xsd#bro_MaximumOperatingLeaseExpirationTerm" xlink:type="locator" xlink:label="bro_MaximumOperatingLeaseExpirationTerm" />
    <link:loc xlink:href="bro-20200630.xsd#bro_FutureLeaseAgreementMember" xlink:type="locator" xlink:label="bro_FutureLeaseAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:type="locator" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:type="locator" xlink:label="us-gaap_TypeOfArrangementAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:type="locator" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_LesseeLeaseDescriptionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_LesseeLeaseDescriptionTable" xlink:to="us-gaap_TypeOfArrangementAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TypeOfArrangementAxis" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:to="bro_FutureLeaseAgreementMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="bro_MaximumOperatingLeaseExpirationTerm" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesRemainderOfFiscalYear" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="bro_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedLeaseLiabilitiesDueInYearTwo" order="10210.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureSegmentInformationAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureSegmentInformationAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureSegmentInformationAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:type="locator" xlink:label="us-gaap_Revenues" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:type="locator" xlink:label="us-gaap_NumberOfReportableSegments" />
    <link:loc xlink:href="bro-20200630.xsd#bro_LondonBermudaAndCaymanIslandsOperationsMember" xlink:type="locator" xlink:label="bro_LondonBermudaAndCaymanIslandsOperationsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain" xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_SegmentGeographicalDomain" xlink:type="locator" xlink:label="srt_SegmentGeographicalDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementGeographicalAxis" xlink:type="locator" xlink:label="srt_StatementGeographicalAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="srt_StatementGeographicalAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_SegmentGeographicalDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_SegmentGeographicalDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_SegmentGeographicalDomain" xlink:to="bro_LondonBermudaAndCaymanIslandsOperationsMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_NumberOfReportableSegments" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_Revenues" order="10170.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureSegmentInformationSummarizedFinancialInformationReportableSegmentsDetails" xlink:href="bro-20200630.xsd#Role_DisclosureSegmentInformationSummarizedFinancialInformationReportableSegmentsDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureSegmentInformationSummarizedFinancialInformationReportableSegmentsDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:type="locator" xlink:label="us-gaap_Assets" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpense" xlink:type="locator" xlink:label="us-gaap_InterestExpense" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:type="locator" xlink:label="us-gaap_AdjustmentForAmortization" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentIncomeNonoperating" xlink:type="locator" xlink:label="us-gaap_InvestmentIncomeNonoperating" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:type="locator" xlink:label="us-gaap_Revenues" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ServicesMember" xlink:type="locator" xlink:label="bro_ServicesMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WholesaleBrokerageMember" xlink:type="locator" xlink:label="bro_WholesaleBrokerageMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NationalProgramsMember" xlink:type="locator" xlink:label="bro_NationalProgramsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetailMember" xlink:type="locator" xlink:label="us-gaap_RetailMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:type="locator" xlink:label="us-gaap_SegmentDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MaterialReconcilingItemsMember" xlink:type="locator" xlink:label="us-gaap_MaterialReconcilingItemsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:type="locator" xlink:label="us-gaap_OperatingSegmentsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain" xlink:type="locator" xlink:label="srt_ConsolidationItemsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis" xlink:type="locator" xlink:label="srt_ConsolidationItemsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="srt_ConsolidationItemsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_ConsolidationItemsAxis" xlink:to="srt_ConsolidationItemsDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidationItemsDomain" xlink:to="us-gaap_OperatingSegmentsMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ConsolidationItemsDomain" xlink:to="us-gaap_MaterialReconcilingItemsMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_StatementBusinessSegmentsAxis" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_SegmentDomain" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_RetailMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_NationalProgramsMember" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_WholesaleBrokerageMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentDomain" xlink:to="bro_ServicesMember" order="10290.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_Revenues" order="11100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_InvestmentIncomeNonoperating" order="11220.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_AdjustmentForAmortization" order="11340.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_Depreciation" order="11460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_InterestExpense" order="11580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="11700.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_Assets" order="11820.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" order="11940.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsSummaryOfAmortizedCostAndFairValuesOfFixedMaturitySecuritiesDetails" xlink:href="bro-20200630.xsd#Role_DisclosureInvestmentsSummaryOfAmortizedCostAndFairValuesOfFixedMaturitySecuritiesDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsSummaryOfAmortizedCostAndFairValuesOfFixedMaturitySecuritiesDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_CorporateDebtSecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:type="locator" xlink:label="us-gaap_USTreasurySecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" order="10040.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2" order="10080.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_USTreasurySecuritiesMember" order="10120.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_CorporateDebtSecuritiesMember" order="10140.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" order="10250.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" order="10410.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities" order="10490.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureInvestmentsAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsHeldByInsuranceRegulators" xlink:type="locator" xlink:label="us-gaap_AssetsHeldByInsuranceRegulators" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleOfOtherInvestments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities" xlink:type="locator" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:type="locator" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BankTimeDepositsMember" xlink:type="locator" xlink:label="us-gaap_BankTimeDepositsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermInvestmentsMember" xlink:type="locator" xlink:label="us-gaap_ShortTermInvestmentsMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeCategorizationMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeCategorizationMember_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:type="locator" xlink:label="us-gaap_InvestmentTypeAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_CorporateDebtSecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:type="locator" xlink:label="us-gaap_USTreasurySecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_USTreasurySecuritiesMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_CorporateDebtSecuritiesMember" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_InvestmentTypeAxis" order="10160.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeCategorizationMember_2" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_InvestmentTypeAxis" xlink:to="us-gaap_InvestmentTypeCategorizationMember" order="10190.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_ShortTermInvestmentsMember" order="10210.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_InvestmentTypeCategorizationMember" xlink:to="us-gaap_BankTimeDepositsMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities" order="10460.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities" order="10780.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ProceedsFromSaleOfOtherInvestments" order="10800.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_AssetsHeldByInsuranceRegulators" order="10850.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsScheduleOfInvestmentsGrossUnrealizedLossAndFairValueDetails" xlink:href="bro-20200630.xsd#Role_DisclosureInvestmentsScheduleOfInvestmentsGrossUnrealizedLossAndFairValueDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInvestmentsScheduleOfInvestmentsGrossUnrealizedLossAndFairValueDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months" xlink:type="locator" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:type="locator" xlink:label="us-gaap_CorporateDebtSecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:type="locator" xlink:label="us-gaap_USTreasurySecuritiesMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:type="locator" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_FinancialInstrumentAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" order="10050.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_FinancialInstrumentAxis" order="10080.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" order="10110.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_USTreasurySecuritiesMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_CorporateDebtSecuritiesMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months" order="10180.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" order="10280.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger" order="10380.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" order="10480.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" order="10580.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss" order="10680.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInsuranceCompanyWNFICAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureInsuranceCompanyWNFICAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureInsuranceCompanyWNFICAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage" xlink:type="locator" xlink:label="us-gaap_PreferredStockDividendRatePercentage" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired" xlink:type="locator" xlink:label="us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired" />
    <link:loc xlink:href="bro-20200630.xsd#bro_NumberOfReinsurers" xlink:type="locator" xlink:label="bro_NumberOfReinsurers" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet" xlink:type="locator" xlink:label="us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PrepaidReinsurancePremiums" xlink:type="locator" xlink:label="us-gaap_PrepaidReinsurancePremiums" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:type="locator" xlink:label="us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CededPremiumsWritten" xlink:type="locator" xlink:label="us-gaap_CededPremiumsWritten" />
    <link:loc xlink:href="bro-20200630.xsd#bro_PercentageOfReinsuranceRecoverablesAllowance" xlink:type="locator" xlink:label="bro_PercentageOfReinsuranceRecoverablesAllowance" />
    <link:loc xlink:href="bro-20200630.xsd#bro_PercentageOfCededPremiums" xlink:type="locator" xlink:label="bro_PercentageOfCededPremiums" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_WrightNationalFloodInsuranceCompanyMember" xlink:type="locator" xlink:label="bro_WrightNationalFloodInsuranceCompanyMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsegmentsDomain" xlink:type="locator" xlink:label="us-gaap_SubsegmentsDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsegmentsDomain" xlink:type="locator" xlink:label="us-gaap_SubsegmentsDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsegmentsAxis" xlink:type="locator" xlink:label="us-gaap_SubsegmentsAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:type="locator" xlink:label="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:type="locator" xlink:label="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:to="us-gaap_SubsegmentsAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsegmentsAxis" xlink:to="us-gaap_SubsegmentsDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsegmentsAxis" xlink:to="us-gaap_SubsegmentsDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SubsegmentsDomain" xlink:to="bro_WrightNationalFloodInsuranceCompanyMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:to="srt_RangeAxis" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10330.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10370.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="bro_PercentageOfCededPremiums" order="10400.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="bro_PercentageOfReinsuranceRecoverablesAllowance" order="10420.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_CededPremiumsWritten" order="10440.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" order="10490.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_PrepaidReinsurancePremiums" order="10510.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve" order="10530.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet" order="10570.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="bro_NumberOfReinsurers" order="10590.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired" order="10640.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" order="10680.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount" order="10720.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_PreferredStockDividendRatePercentage" order="10760.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentLineItems" xlink:to="us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval" order="10840.00" priority="2" use="optional" />
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureShareholdersEquityAdditionalInformationDetails" xlink:href="bro-20200630.xsd#Role_DisclosureShareholdersEquityAdditionalInformationDetails" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.bbinsurance.com/20200630/taxonomy/role/DisclosureShareholdersEquityAdditionalInformationDetails">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:type="locator" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1" />
    <link:loc xlink:href="bro-20200630.xsd#bro_AcceleratedShareRepurchaseAgreementMember" xlink:type="locator" xlink:label="bro_AcceleratedShareRepurchaseAgreementMember" />
    <link:loc xlink:href="bro-20200630.xsd#bro_ThirdAcceleratedShareRepurchaseAgreementMember" xlink:type="locator" xlink:label="bro_ThirdAcceleratedShareRepurchaseAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:type="locator" xlink:label="srt_MinimumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:type="locator" xlink:label="srt_MaximumMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:type="locator" xlink:label="srt_RangeMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:type="locator" xlink:label="srt_RangeAxis" />
    <link:loc xlink:href="bro-20200630.xsd#bro_SecondAcceleratedShareRepurchaseAgreementMember" xlink:type="locator" xlink:label="bro_SecondAcceleratedShareRepurchaseAgreementMember" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramDomain_2" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:type="locator" xlink:label="us-gaap_ShareRepurchaseProgramAxis" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcceleratedShareRepurchasesTable" xlink:type="locator" xlink:label="us-gaap_AcceleratedShareRepurchasesTable" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AcceleratedShareRepurchasesLineItems" xlink:type="locator" xlink:label="us-gaap_AcceleratedShareRepurchasesLineItems" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_AcceleratedShareRepurchasesLineItems" xlink:to="us-gaap_AcceleratedShareRepurchasesTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_AcceleratedShareRepurchasesTable" xlink:to="us-gaap_ShareRepurchaseProgramAxis" order="10040.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain_2" order="10050.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ShareRepurchaseProgramAxis" xlink:to="us-gaap_ShareRepurchaseProgramDomain" order="10070.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="bro_SecondAcceleratedShareRepurchaseAgreementMember" order="10090.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_AcceleratedShareRepurchasesTable" xlink:to="srt_RangeAxis" order="10100.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="srt_RangeAxis" xlink:to="srt_RangeMember" order="10130.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MaximumMember" order="10150.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="srt_RangeMember" xlink:to="srt_MinimumMember" order="10170.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="bro_ThirdAcceleratedShareRepurchaseAgreementMember" order="10230.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareRepurchaseProgramDomain" xlink:to="bro_AcceleratedShareRepurchaseAgreementMember" order="10270.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AcceleratedShareRepurchasesLineItems" xlink:to="us-gaap_StockRepurchaseProgramAuthorizedAmount1" order="10300.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AcceleratedShareRepurchasesLineItems" xlink:to="us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" order="10350.00" priority="2" use="optional" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AcceleratedShareRepurchasesLineItems" xlink:to="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" order="10390.00" priority="2" use="optional" />
  </link:definitionLink>
</link:linkbase>
