Entries linking to larkspur
songbird of the Old World, early 14c., earlier lauerche (c. 1200), from Old English lawerce (late Old English laferce), from Proto-Germanic *laiw(a)rikon (source also of Old Saxon lewerka, Frisian liurk, Old Norse lævirik, Dutch leeuwerik, German Lerche), a word of unknown origin.
Old English and Old Norse forms suggest a contracted compound, perhaps meaning "treason-worker," but "nothing is known in folklore to account for such a designation" [OED]. Noted for its early song and high flying (in contrast to its low nest). When the sky falls, we shall catch larks was an old proverb mocking foolish optimism.
Latin alauda "the lark" (source of Italian aloda, Spanish alondra, Provençal alauza, Old French aloe) is said to be from Gaulish (Celtic). True Latin names for the skylark were galerita, corydalus.
SPLIT the lark and you’ll find the music,
Bulb after bulb, in silver rolled
Generalized sense of "anything that urges on, stimulus," is from late 14c. As a sharp projection on the leg of a cock, from 1540s. Meaning "a ridge projecting off a mountain mass" is recorded from 1650s. Of railway lines from 1837. "Widely extended senses ... are characteristic of a horsey race" [Weekley]. Expression on the spur of the moment (1801) preserves archaic phrase on the spur "in great haste" (1520s). To win one's spurs is to gain knighthood by some valorous act, gilded spurs being the distinctive mark of a knight.