Difference of Trailer, Full Trailer, Semi-Trailer, Trailer Truck

A trailer is an unpowered vehicle towed by a powered vehicle. It is commonly used for the transport of goods and materials.

A full trailer is a trailer supported by front and rear axles and pulled by a drawbar. It is a towed vehicle having at least two axles, and equipped with a towing device which can move vertically in relation to the trailer and controls the direction of the front axle, but which transmits no significant static load to the towing vehicle. This style of trailer is also popular for use with farm tractors.

A semi-trailer is a trailer without a front axle. It may refer to the combination of a truck and a semi-trailer, a tractor-trailer in the USA market. A large proportion of a semi-trailer's weight is supported by a tractor unit, or a detachable front-axle assembly known as a dolly, or the tail of another trailer. The other portion of the semi-trailer's weight is semi-supported (half supported) by its own wheels, which only support the rear of the semi-trailer. A semi-trailer is normally equipped with landing gear (legs which can be lowered) to support it when it is uncoupled.

A semi-tractor-trailer truck is the combination of a tractor unit and one, or more, semi-trailers to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth-wheel. It is variously known as a transport truck, semi-trailer truck, tractor-trailer truck, semi-tractor truck, semi-truck, trailer truck, tractor truck, transfer truck, articulated truck, artic, single truck, semi-tractor-trailer, semi-trailer, tractor-trailer, semi-tractor, semi, trailer, tractor, big rig, eighteen-wheeler and articulated lorry, depending on the country.