Tractor unit - Wikipedia
A tractor unit (also known as a truck unit, prime mover, ten-wheeler, mack, semi-tractor, semi-truck, tractor cab, truck cab, tractor rig, truck rig or big rig or simply a tractor, truck or rig) is a characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load. These fall into two categories: heavy- and medium-duty military and commercial rear
Get a Quote