first-class 词源(Etymology) - 优词词源[英文版]

first-class (adj.)[first-class 词源字典]: "of the highest class" with reference to some standard of excellence, 1837, from first (adj.) + class (n.). Specifically in reference to conveyances for travel, 1846. In reference to U.S. Mail, 1875.[first-class etymology, first-class origin, 英语词源]