Topic >> Animals: Insects and Small Creatures caterpillarcat‧er‧pil‧lar /ˈkæt̮ɚˌpɪlɚ, ˈkæt̮ə-/ noun [countable] Word Origin a small creature with a long rounded body and many legs that develops into a butterfly or moth [Origin: 1400–1500 Old North French catepelose “hairy cat, caterpillar”]