The Collaborative International Dictionary of English v.0.48:
Caterpillar track \Cat"er*pil`lar track\, n. an endless belt looped over several wheels, used in pairs in place of wheels to propel vehicles, such as tractors or military tanks, over rough ground. [PJC]WordNet (r) 3.0 (2006):
caterpillar track n 1: an endless metal belt on which tracked vehicles move over the ground [syn: track, caterpillar track, caterpillar tread]