[sem-i-trey-ler] 
| 1. | Also called semi. a detachable trailer for hauling freight, with wheels at the rear end, the forward end being supported by the rear of a truck tractor when attached. Compare full trailer. |
| 2. | tractor-trailer. |
[trak-ter-trey-ler] | a combination trucking unit consisting of a tractor hooked up to a full trailer or a semitrailer. Also called semitrailer, semitruck. Compare rig 1 (def. 10). |
ɪˌtreɪ