From Longman Dictionary of Contemporary Englishcaterpillarcat‧er‧pil‧lar /ˈkætəˌpɪlə $ -tərˌpɪlər/ noun [countable] 
HBIa small creature like a worm with many legs that eats leaves and that develops into a butterfly or other flying insect
HBIa small creature like a worm with many legs that eats leaves and that develops into a butterfly or other flying insectExamples from the Corpus
caterpillar• Just as only a caterpillar can become a butterfly, the formal stage seems a necessary developmental step to the skilful stage.• In the Washington area, cabbages are vulnerable to two persistent pests: Aphids and cabbage moth caterpillars.• The old caterpillar skin peels back and falls away.• When I arrived at the page on caterpillars, again I read the bold headings.• It may take as long as a week for all the caterpillars to make their chrysalises.• As the wasp hovered near, the caterpillars suddenly started flailing from side to side.• The caterpillars can be picked off, but their coloring makes them difficult to see, especially when they are small.CaterpillarCaterpillar (also Caterpillar track) noun [countable] trademark TTCa metal belt made of short connected pieces that is fastened over the wheels of a heavy vehicle to help it to move over soft ground a Caterpillar tractor (=a vehicle fitted with this belt)Examples from the Corpus
Caterpillar• Solar Turbines is a subsidiary of Illinois-based Caterpillar Inc., which until recently has been involved in a bitter union strike.• In this collection, he has embraced Caterpillar work boots, done up for him in two-tone suede.• There was no Caterpillar Club yet, no way out of a doomed plane.• That strike ended in the spring of 1992, when Caterpillar made headlines by threatening to permanently replace the strikers.Origin caterpillar (1400-1500) Old North French catepelose “hairy cat, caterpillar” 