relaxation (n.)youdaoicibaDictYouDict[relaxation 词源字典]
late 14c., "rupture; mid-15c., "remission of a burden or penalty," from Old French relaxacion (14c.) and directly from Latin relaxationem (nominative relaxatio) "an easing, mitigation, relaxation," noun of action from past participle stem of relaxare (see relax). Meaning "relief from hard work or ordinary cares" is from 1540s.[relaxation etymology, relaxation origin, 英语词源]