<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5c -->
    <!-- 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/2026/oef-2026.xsd#HoldingsByIndustrySector" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByIndustrySector" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByGeographicRegion" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByGeographicRegion" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByCreditQuality" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByCreditQuality" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByMaturity" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByMaturity" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByAssetCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByAssetCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByOtherCategory" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingsByOtherCategory2" roleURI="http://xbrl.sec.gov/oef/role/HoldingsByOtherCategory2" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#LargestHoldings" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldings" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ProspectusOnly" roleURI="http://xbrl.sec.gov/rr/role/ProspectusOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#RiskOnly" roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#CoregistrantOnly" roleURI="http://xbrl.sec.gov/oef/role/CoregistrantOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingAssetCategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingAssetCategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#BroadBasedIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/BroadBasedIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#AdditionalIndexOnly" roleURI="http://xbrl.sec.gov/oef/role/AdditionalIndexOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#IndustrySectorOnly" roleURI="http://xbrl.sec.gov/oef/role/IndustrySectorOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#GeographicRegionOnly" roleURI="http://xbrl.sec.gov/oef/role/GeographicRegionOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#CreditQualityOnly" roleURI="http://xbrl.sec.gov/oef/role/CreditQualityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#MaturityOnly" roleURI="http://xbrl.sec.gov/oef/role/MaturityOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#Other1CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other1CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#Other2CategoryOnly" roleURI="http://xbrl.sec.gov/oef/role/Other2CategoryOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#LargestHoldingOnly" roleURI="http://xbrl.sec.gov/oef/role/LargestHoldingOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#SalesLoadOnly" roleURI="http://xbrl.sec.gov/oef/role/SalesLoadOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#HoldingMeasureOnly" roleURI="http://xbrl.sec.gov/oef/role/HoldingMeasureOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.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/2026/oef-2026.xsd#oef_AllRisksMember" xlink:label="loc_oefAllRisksMember" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_EquityMarketRiskMember" xlink:label="loc_vistasharesEquityMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesEquityMarketRiskMember" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_DerivativesRiskMember" xlink:label="loc_vistasharesDerivativesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesDerivativesRiskMember" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_OptionsContractsMember" xlink:label="loc_vistasharesOptionsContractsMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesOptionsContractsMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_CounterpartyRiskMember" xlink:label="loc_vistasharesCounterpartyRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesCounterpartyRiskMember" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_EconomicAndMarketRiskMember" xlink:label="loc_vistasharesEconomicAndMarketRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesEconomicAndMarketRiskMember" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_UnderlyingEtfRiskMember" xlink:label="loc_vistasharesUnderlyingEtfRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesUnderlyingEtfRiskMember" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_ActiveManagementRiskMember" xlink:label="loc_vistasharesActiveManagementRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesActiveManagementRiskMember" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_MarketCapitalizationRiskMember" xlink:label="loc_vistasharesMarketCapitalizationRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesMarketCapitalizationRiskMember" xlink:type="arc" order="70" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_LargecapitalizationInvestingMember" xlink:label="loc_vistasharesLargecapitalizationInvestingMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesLargecapitalizationInvestingMember" xlink:type="arc" order="80" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_EtfRisksMember" xlink:label="loc_vistasharesEtfRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesEtfRisksMember" xlink:type="arc" order="90" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_AuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" xlink:label="loc_vistasharesAuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesAuthorizedParticipantsMarketMakersAndLiquidityProvidersConcentrationRiskMember" xlink:type="arc" order="100" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_CostsOfBuyingOrSellingSharesMember" xlink:label="loc_vistasharesCostsOfBuyingOrSellingSharesMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesCostsOfBuyingOrSellingSharesMember" xlink:type="arc" order="110" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_SharesMayTradeAtPricesOtherThanNavMember" xlink:label="loc_vistasharesSharesMayTradeAtPricesOtherThanNavMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesSharesMayTradeAtPricesOtherThanNavMember" xlink:type="arc" order="120" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_TradingMember" xlink:label="loc_vistasharesTradingMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesTradingMember" xlink:type="arc" order="130" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_NewFundRiskMember" xlink:label="loc_vistasharesNewFundRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesNewFundRiskMember" xlink:type="arc" order="140" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_NewerSubadviserRiskMember" xlink:label="loc_vistasharesNewerSubadviserRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesNewerSubadviserRiskMember" xlink:type="arc" order="150" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_OperationalRiskMember" xlink:label="loc_vistasharesOperationalRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesOperationalRiskMember" xlink:type="arc" order="160" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_USGovernmentandUSAgencyObligationsRiskMember" xlink:label="loc_vistasharesUSGovernmentandUSAgencyObligationsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesUSGovernmentandUSAgencyObligationsRiskMember" xlink:type="arc" order="170" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_ForeignSecuritiesRiskMember" xlink:label="loc_vistasharesForeignSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesForeignSecuritiesRiskMember" xlink:type="arc" order="180" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_CurrencyExchangeRateRiskMember" xlink:label="loc_vistasharesCurrencyExchangeRateRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesCurrencyExchangeRateRiskMember" xlink:type="arc" order="190" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_DepositaryReceiptRiskMember" xlink:label="loc_vistasharesDepositaryReceiptRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesDepositaryReceiptRiskMember" xlink:type="arc" order="200" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_DevelopedMarketsRiskMember" xlink:label="loc_vistasharesDevelopedMarketsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesDevelopedMarketsRiskMember" xlink:type="arc" order="210" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_MidCapitalizationInvestingMember" xlink:label="loc_vistasharesMidCapitalizationInvestingMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesMidCapitalizationInvestingMember" xlink:type="arc" order="220" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_EmergingMarketsRiskMember" xlink:label="loc_vistasharesEmergingMarketsRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesEmergingMarketsRiskMember" xlink:type="arc" order="230" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_SmallcapitalizationInvestingMember" xlink:label="loc_vistasharesSmallcapitalizationInvestingMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesSmallcapitalizationInvestingMember" xlink:type="arc" order="240" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_TechnologySectorRiskMember" xlink:label="loc_vistasharesTechnologySectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesTechnologySectorRiskMember" xlink:type="arc" order="250" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_CommodityRiskMember" xlink:label="loc_vistasharesCommodityRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesCommodityRiskMember" xlink:type="arc" order="260" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_EtnRisksMember" xlink:label="loc_vistasharesEtnRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesEtnRisksMember" xlink:type="arc" order="270" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_FixedIncomeRiskMember" xlink:label="loc_vistasharesFixedIncomeRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesFixedIncomeRiskMember" xlink:type="arc" order="280" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_CreditRisksMember" xlink:label="loc_vistasharesCreditRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesCreditRisksMember" xlink:type="arc" order="290" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_HighYieldSecuritiesRiskMember" xlink:label="loc_vistasharesHighYieldSecuritiesRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesHighYieldSecuritiesRiskMember" xlink:type="arc" order="300" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_InterestRateRisksMember" xlink:label="loc_vistasharesInterestRateRisksMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesInterestRateRisksMember" xlink:type="arc" order="310" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_UtilitiesSectorRiskMember" xlink:label="loc_vistasharesUtilitiesSectorRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesUtilitiesSectorRiskMember" xlink:type="arc" order="320" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_RealEstateRiskMember" xlink:label="loc_vistasharesRealEstateRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesRealEstateRiskMember" xlink:type="arc" order="330" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_DistributionRiskMember" xlink:label="loc_vistasharesDistributionRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesDistributionRiskMember" xlink:type="arc" order="340" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_HighDividendStyleRiskMember" xlink:label="loc_vistasharesHighDividendStyleRiskMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefAllRisksMember" xlink:to="loc_vistasharesHighDividendStyleRiskMember" xlink:type="arc" order="350" />
    </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/2026/dei-2026.xsd#dei_EntityDomain" xlink:label="loc_deiEntityDomain" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106824Member" xlink:label="loc_vistasharesS000106824Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106824Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106820Member" xlink:label="loc_vistasharesS000106820Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106820Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106821Member" xlink:label="loc_vistasharesS000106821Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106821Member" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106823Member" xlink:label="loc_vistasharesS000106823Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106823Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106822Member" xlink:label="loc_vistasharesS000106822Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106822Member" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106818Member" xlink:label="loc_vistasharesS000106818Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106818Member" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106817Member" xlink:label="loc_vistasharesS000106817Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106817Member" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_S000106819Member" xlink:label="loc_vistasharesS000106819Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_deiEntityDomain" xlink:to="loc_vistasharesS000106819Member" xlink:type="arc" order="70" />
    </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/2026/oef-2026.xsd#oef_ShareClassDomain" xlink:label="loc_oefShareClassDomain" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277710Member" xlink:label="loc_vistasharesC000277710Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277710Member" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277706Member" xlink:label="loc_vistasharesC000277706Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277706Member" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277707Member" xlink:label="loc_vistasharesC000277707Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277707Member" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277709Member" xlink:label="loc_vistasharesC000277709Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277709Member" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277708Member" xlink:label="loc_vistasharesC000277708Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277708Member" xlink:type="arc" order="40" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277704Member" xlink:label="loc_vistasharesC000277704Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277704Member" xlink:type="arc" order="50" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277703Member" xlink:label="loc_vistasharesC000277703Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277703Member" xlink:type="arc" order="60" />
      <link:loc xlink:type="locator" xlink:href="vistashares-20260909.xsd#vistashares_C000277705Member" xlink:label="loc_vistasharesC000277705Member" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_oefShareClassDomain" xlink:to="loc_vistasharesC000277705Member" xlink:type="arc" order="70" />
    </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>
