Definition
A caterpillar is the wormlike larva of a butterfly or moth; any of various insect larvae similar to those of the butterfly or moth.
Etymology. c.1440, catyrpel, probably altered (by association with M.E. piller "plunderer") from Norm.-Fr. caterpilose, from O.Fr. chatepelose, lit. "hairy cat" (probably in ref. to the "wooly-bear" variety), from L.L. catta "cat" + pilosus "hair." A Swiss Ger. name for it is teufelskatz "devil's cat." Caterpillar tractor is from 1908.