A federal court's decision to refrain from deciding a matter over which it has jurisdiction where a state court is capable of hearing and rendering a final determination in the matter. Abstention is designed to promote federal-state relations and provides a vehicle for a federal court to refrain from ruling on constitutional questions even though it has jurisdiction to hear the controversy. It is rarely invoked because it deprives litigants of their right to have certain types of controversies resolved in a federal court.