a la modeyoudaoicibaDictYouDict[a la mode 词源字典]
1640s, from French à la mode (15c.), literally "in the fashion" (see mode (n.2)). In 17c., sometimes nativized as all-a-mode. Cookery sense of a dessert served with ice cream is 1903, American English.[a la mode etymology, a la mode origin, 英语词源]