"songbird," O.E. lawerce (late O.E. laferce), from P.Gmc. *laiw(a)rikon (cf. O.S. lewerka, O.N. lævirik, Du. leeuwerik, Ger. Lerche), of unknown origin. Some O.E. and O.N. forms suggest a compound meaning "treason-worker," but there is no folk tale to explain or support this. The plant larkspur (1578) is so called from resemblance to the bird's large hind claws.
"spree, frolic," 1811, possibly shortening of skylark (1809), sailors' slang "play rough in the rigging of a ship" (larks were proverbial for high-flying), or from Eng. dial. lake/laik "to play" (c.1300, from O.N. leika "to play") with intrusive -r- common in southern British dialect. The verb lake, considered characteristic of Northern English vocabulary, is the opposite of work but lacks the other meanings of play.