The tractor simply means that the front of the car is towed with tools (that is, the front of the car can be separated from the original car box and tow other cars, and the car box can also be separated from the original front of the car and be towed by other fronts) General large trucks (Semi-trailer).
The difference between a trailer tractor and a semi-trailer tractor
The front of the vehicle with driving capability is called a tractor, and the vehicle with no driving capability behind it is called a trailer, and the trailer is towed away by the tractor. There are two ways to connect the tractor and the trailer: the first is that the front half of the trailer is placed on the towing saddle above the rear section of the tractor, and the bridge behind the tractor bears part of the trailer's weight, which is a semi-trailer; One is that the front end of the trailer is connected to the rear end of the tractor. The tractor only provides forward pulling force and drags the trailer, but does not bear the downward weight of the trailer. This is a full trailer.