<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByIndustrySector" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByIndustrySector" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByGeographicRegion" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByGeographicRegion" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByCreditQuality" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByCreditQuality" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByMaturity" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByMaturity" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByAssetCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByAssetCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByOtherCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingsByOtherCategory2" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory2" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#LargestHoldings" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldings" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ProspectusOnly" roleURI="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#RiskOnly" roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#CoregistrantOnly" roleURI="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingAssetCategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#BroadBasedIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#AdditionalIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#IndustrySectorOnly" roleURI="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#GeographicRegionOnly" roleURI="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#CreditQualityOnly" roleURI="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#MaturityOnly" roleURI="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#Other1CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#Other2CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#LargestHoldingOnly" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SalesLoadOnly" roleURI="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#HoldingMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ValueMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
    <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: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#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <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:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember" xlink:label="loc_oefAllRisksMember" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_AsianInvestmentsRiskMember" xlink:label="loc_rbbAsianInvestmentsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbAsianInvestmentsRiskMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_CurrencyRiskMember" xlink:label="loc_rbbCurrencyRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbCurrencyRiskMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_CyberSecurityRiskMember" xlink:label="loc_rbbCyberSecurityRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbCyberSecurityRiskMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_DepositaryReceiptRiskMember" xlink:label="loc_rbbDepositaryReceiptRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbDepositaryReceiptRiskMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_EmergingMarketsRiskMember" xlink:label="loc_rbbEmergingMarketsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbEmergingMarketsRiskMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_EquitySecuritiesRiskMember" xlink:label="loc_rbbEquitySecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbEquitySecuritiesRiskMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_EtfRiskMember" xlink:label="loc_rbbEtfRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbEtfRiskMember" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_AuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" xlink:label="loc_rbbAuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbAuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" xlink:type="arc" order="70" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_SecondaryMarketTradingRiskMember" xlink:label="loc_rbbSecondaryMarketTradingRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbSecondaryMarketTradingRiskMember" xlink:type="arc" order="80" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_SharesMayTradeAtPricesOtherThanNAVRiskMember" xlink:label="loc_rbbSharesMayTradeAtPricesOtherThanNAVRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbSharesMayTradeAtPricesOtherThanNAVRiskMember" xlink:type="arc" order="90" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_EuropeanInvestmentsRiskMember" xlink:label="loc_rbbEuropeanInvestmentsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbEuropeanInvestmentsRiskMember" xlink:type="arc" order="100" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ForeignCustodyRiskMember" xlink:label="loc_rbbForeignCustodyRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbForeignCustodyRiskMember" xlink:type="arc" order="110" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ForeignSecuritiesRiskMember" xlink:label="loc_rbbForeignSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbForeignSecuritiesRiskMember" xlink:type="arc" order="120" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_InflationAndDeflationRiskMember" xlink:label="loc_rbbInflationAndDeflationRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbInflationAndDeflationRiskMember" xlink:type="arc" order="130" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_InkindContributionRiskMember" xlink:label="loc_rbbInkindContributionRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbInkindContributionRiskMember" xlink:type="arc" order="140" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_LargeCapitalizationCompaniesRiskMember" xlink:label="loc_rbbLargeCapitalizationCompaniesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbLargeCapitalizationCompaniesRiskMember" xlink:type="arc" order="150" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_LargeShareholderRiskMember" xlink:label="loc_rbbLargeShareholderRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbLargeShareholderRiskMember" xlink:type="arc" order="160" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ManagementRiskMember" xlink:label="loc_rbbManagementRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbManagementRiskMember" xlink:type="arc" order="170" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_MarketRiskMember" xlink:label="loc_rbbMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbMarketRiskMember" xlink:type="arc" order="180" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_MlpRiskMember" xlink:label="loc_rbbMlpRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbMlpRiskMember" xlink:type="arc" order="190" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_NewAdviserRiskMember" xlink:label="loc_rbbNewAdviserRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbNewAdviserRiskMember" xlink:type="arc" order="200" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_NewFundRiskMember" xlink:label="loc_rbbNewFundRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbNewFundRiskMember" xlink:type="arc" order="210" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_OperationalRiskMember" xlink:label="loc_rbbOperationalRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbOperationalRiskMember" xlink:type="arc" order="220" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_PreferredStockRiskMember" xlink:label="loc_rbbPreferredStockRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbPreferredStockRiskMember" xlink:type="arc" order="230" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_QuantitativeInvestingRiskMember" xlink:label="loc_rbbQuantitativeInvestingRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbQuantitativeInvestingRiskMember" xlink:type="arc" order="240" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ReitRiskMember" xlink:label="loc_rbbReitRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbReitRiskMember" xlink:type="arc" order="250" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ResearchProviderRisksMember" xlink:label="loc_rbbResearchProviderRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbResearchProviderRisksMember" xlink:type="arc" order="260" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_SectorRiskMember" xlink:label="loc_rbbSectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbSectorRiskMember" xlink:type="arc" order="270" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_InformationTechnologySectorRiskMember" xlink:label="loc_rbbInformationTechnologySectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbInformationTechnologySectorRiskMember" xlink:type="arc" order="280" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_SmallAndMediumCapitalizationCompaniesRiskMember" xlink:label="loc_rbbSmallAndMediumCapitalizationCompaniesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbSmallAndMediumCapitalizationCompaniesRiskMember" xlink:type="arc" order="290" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_UnderlyingFundsRiskMember" xlink:label="loc_rbbUnderlyingFundsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbUnderlyingFundsRiskMember" xlink:type="arc" order="300" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_ValueInvestmentStrategyRiskMember" xlink:label="loc_rbbValueInvestmentStrategyRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_rbbValueInvestmentStrategyRiskMember" xlink:type="arc" order="310" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_S000101983Member" xlink:label="loc_rbbS000101983Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_rbbS000101983Member" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="loc_oefShareClassDomain" />
      <link:loc xlink:type="locator" xlink:href="rbb-20260511.xsd#rbb_C000272400Member" xlink:label="loc_rbbC000272400Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_rbbC000272400Member" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ValueMeasureOnly" />
</link:linkbase>
