nondeductible terminable interest rule

noun | \ ˌnän-di-ˈdək-tə-bəl- \ | non·de·duc·ti·ble terminable interest rule

1. : a rule in estate tax law: the value of a property interest that passes to a surviving spouse may not qualify for the marital deduction if it passes from the surviving spouse to another person for less than adequate consideration upon the happening of some event (as the passing of a period of time) — see also qualified terminable interest property at property