The Collaborative International Dictionary of English v.0.48:

half-track \half-track\, half-tracked \half-tracked\adj.
   having caterpillar treads on the rear and wheels in front;
   as, half-track armored vehicles.

   Syn: half-track.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

half-track \half-track\ n.
   a half-tracked vehicle; -- used mostly of armored military
   vehicles.
   [PJC]

WordNet (r) 3.0 (2006):

half-track
    adj 1: having caterpillar treads on the rear and wheels in
           front; "half-track armored vehicles" [syn: half-track,
           half-tracked]