employ 词源(Etymology) - 趣词词源[英文版]

employ [employ 词源字典]: employ: [15] Essentially, employ is the same word as imply [14] and implicate [16]. All three come ultimately from Latin implicāre ‘enfold, involve’, a compound verb formed from the prefix in- ‘in’ and plicāre ‘fold’ (source of English ply and related to English fold). This passed into Old French as emplier, which in turn was transmitted into English as imply; this originally retained the literal sense ‘enfold’, and it was only gradually that the metaphorical ‘involve as a necessary condition’ developed.

However, Old French emplier had a variant empleier, later emploier, which took a slightly different semantic route – from simply ‘involve’ to ‘involve in or apply to a particular purpose’. This was the sense in which English acquired it as employ.
=> fold, implicate, imply, ply[employ etymology, employ origin, 英语词源]
employ (v.): early 15c., "apply or devote (something to some purpose); expend or spend," from Old French emploiier (12c.) "make use of, apply; increase; entangle; devote," from Latin implicare "enfold, involve, be connected with, unite, associate," from assimilated form of in- (see in- (2)) + plicare "to fold" (see ply (v.1)). Imply, which is the same word, retains more of the original sense. Sense of "hire, engage" first recorded in English 1580s, from meaning "involve in a particular purpose," which arose in Late Latin. Related: Employed; employing; employable.
employ (n.): 1660s, "action of employing," from French emploi, from Middle French verb employer (see employ (v.)). From 1709 as "state of being employed."