caterpillar (n.)

"larva of a butterfly or moth," mid-15c., catyrpel, probably altered (by association with Middle English piller "plunderer;" see pillage (n.)) from Old North French caterpilose "caterpillar" (Old French chatepelose), literally "shaggy cat" (probably in reference to the "wooly-bear" variety), from Late Latin catta pilosa, from catta "cat" (see cat (n.)) + pilosus "hairy, shaggy, covered with hair," from pilus "hair" (see pile (n.3)).

Compare also French chenille "caterpillar," literally "little dog." A Swiss German name for it is teufelskatz "devil's cat." "The caterpillar has in many idioms received the name of other animals" [Kitchin, who cites also Milanese cagnon "little dog," Italian dialectal gattola "little cat," Kentish hop-dog, hop-cat, Portuguese lagarta "lizard."] Compare also American English wooly-bear for the hairy variety. An Old English name for it was cawelworm "cole-worm." Caterpillar tractor, one which travels on endless steel belts, is from 1908, so called from its way of moving.

updated on November 18, 2018

Definitions of caterpillar from WordNet
caterpillar (n.)
a wormlike and often brightly colored and hairy or spiny larva of a butterfly or moth;
Caterpillar (n.)
a large tracked vehicle that is propelled by two endless metal belts; frequently used for moving earth in construction and farm work;
Synonyms: cat
Etymologies are not definitions. From, not affiliated with etymonline.