cre·tion \ˈkrēshən\noun (-s) Etymology: Latin cretion-, cretio, from cretus (past participle of cernere to cern, discern) + -ion-, -io -ion — more at certain 1.Roman law: an act before a magistrate by which an outside heir declares his acceptance of the succession 2.Roman law: the time allowed an heir to make his decision of cretion — compare jus deliberandi • cre·tion·ary\-əˌnerē\adjective