cohabitation (n.)youdaoicibaDictYouDict[cohabitation 词源字典]
mid-15c., "action or state of living together (especially as husband and wife)," from Middle French cohabitation (Old French cohabitacion "cohabitation, sexual intercourse"), from Late Latin cohabitationem (nominative cohabitatio), noun of action from past participle stem of cohabitare "to dwell together," from co- "with, together" (see co-) + habitare "to live, dwell" (see habitat).[cohabitation etymology, cohabitation origin, 英语词源]