duration (n.)youdaoicibaDictYouDict[duration 词源字典]
late 14c., from Old French duration, from Medieval Latin durationem (nominative duratio), noun of action from past participle stem of Latin durare "harden" (see endure). Old legalese phrase for the duration popularized 1916 in reference to British enlistments in World War I.[duration etymology, duration origin, 英语词源]