Oh, go on then, let’s have another word. In writing about frass, I was minded to wonder about the origin of caterpillar, so …
Caterpillar
1. The larva of a butterfly or moth; sometimes extended to those of other insects, especially those of saw-flies, which are also hairy.
2. A type of tractor which travels upon two endless steel bands, one on each side of the machine, to facilitate travel over very rough ground. (And by extension to other such vehicles.)
3. To move like a caterpillar or on caterpillar tracks.
The first uses, in sense 1, recorded by the OED is from c.1440 in Promptorium Parvulorum 63: Catyrpel, wyrm among frute, erugo.
I’m going to reproduce the etymology from the OED essentially in full:
Etymology: Catyrpel, in Promptorium Parvulorum, may be merely an error of the scribe for catyrpelour (or -er); [later sources have] the full form. Generally compared with the synonymous Old French chatepelose, literally ‘hairy or downy cat’ (compare the Scots name hairy woubit, ‘woolly bear’), of which the Old Northern French would be catepelose. This is a possible source, though no connection is historically established: the final sibilant might be treated in English as a plural formative, and the supposed singular catepelo would be readily associated with the well-known word piller, pilour, pillager, plunderer, spoiler. This is illustrated by the fact that in the figurative sense, piller and caterpiller are used synonymously in a large number of parallel passages. The regular earlier spelling was with -er; the corruption caterpillar (?after pillar), occasional in the 17th century, was adopted by Johnson, and has since prevailed.
(Some think the word a direct compound of piller. The giving to hairy caterpillars a name derived from the cat, is seen not only in the French word cited, but also in Lombard gatta, gattola (cat, kitten), Swiss teufelskatz (devil’s cat); compare also French chenille (from canicula, little dog), Milanese can, cagnon (dog, pup). Compare also catkin, French chaton, applied to things resembling hairy caterpillars.)
In other words, we don’t know!