Word Origin & History
lock"means of fastening," O.E. loc "bolt, fastening, enclosure," from P.Gmc. *lokom/*lukom (cf. O.N. lok "fastening, lock," Goth. usluks "opening," O.H.G. loh "dungeon," Ger. Loch "opening, hole," Du. luck "shutter, trapdoor"). "The great diversity of meaning in the Teut. words seems to indicate two or more
independent but formally identical substantival formations from the root." The river sense is from c.1300, on notion of "barrier, enclosure." Wrestling sense is from c.1600. The verb is c.1300, from O.E. lucan "to lock, to close" (class II strong verb; past tense leac, pp. locen). Slang lock horns "fight" is from 1839. Lock-up "detention cell for offenders" is from 1839.
lock"tress of hair," from O.E. locc, from P.Gmc. *lukkoz (cf. O.N. lokkr, O.Fris., Du. lok, Ger. Locke "lock of hair"), from PIE *lugnos-, from base *lug- "to bend, to twist" (cf. Gk. lygos "pliant twig, withe," Lith. lugnas "flexible").