Pronunciation: (haf'trak", häf'-),[key] —n. 1. a caterpillar tread that runs over and under the rear or driving wheels of a vehicle but is not connected with the forward wheels: used esp. on military vehicles.
2. a motor vehicle with rear driving wheels on caterpillar treads.
3. Mil.an armored vehicle equipped with half-tracks. Also,half'track".