adieuyoudaoicibaDictYouDict[adieu 词源字典]
late 14c., adewe, from French adieu, from phrase a dieu (vous) commant "I commend (you) to God," from a "to" (see ad) + dieu "God," from Latin deum, accusative of deus "god," from PIE *deiwos (see Zeus). Originally said to the party left; farewell was to the party setting forth.[adieu etymology, adieu origin, 英语词源]