ply

\ \ English has two distinct words ply, although ultimately they are related. The one meaning ‘fold, twist, layer’ [14], now mainly found in plywood [20] and in combinations such as twoply and three-ply, comes from Old French pli, a derivative of the verb plier ‘bend, fold’ (source of English apply [14], pliable [15], pliant [14], pliers [16], and reply). This went back to Latin plicāre ‘fold’, a relative of English fold and source of accomplice, complicate [17], employ, explicit, imply, pleat, plight ‘predicament’, and supplicate. It was formed from a base that also produced English perplex [16] and the final syllables of simple and supple. The apple pie of apple-pie bed [18] is thought to be an alteration of French nappe pliée ‘folded sheet’. Ply ‘travel a route regularly’ or ‘solicit’ (as in ‘ply for hire’) [14] is short for apply, a relative of ply ‘fold’, and originally meant ‘apply, employ’ (as in ‘ply one’s needle’).

\ \ Cf.⇒ ACCOMPLICE, APPLY, COMPLICATE, COMPLY, DOUBLE, EMPLOY, EXPLICIT, FOLD, IMPLY, PERPLEX, PLEAT, PLIABLE, PLIERS, PLIGHT, REPLY, SIMPLE, SUPPLE, SUPPLICATE