You can do a workaround using the TaxCatchAll field as long as you know which terms belong to which taxonomy field - if you have multiple.
/_api/web/Lists/GetByTitle('<list>')/Items/?$select=*,TaxCatchAll/Term$filter=TaxCatchAllTerm&$filter=TaxCatchAll/Term eq 'Puzzlepart'&$expand=TaxCatchAll