1560s, lagarto (modern form attested from 1620s, with excrescent -r as in tater, feller, etc.), a corruption of Spanish el lagarto (de Indias) "the lizard (of the Indies)," from Latin lacertus (see lizard). Alligarter was an early variant. The slang meaning "non-playing devotee of swing music" is attested from 1936; the phrase see you later, alligator is from a 1956 song title.