Conventional style cab tractorA cab-over semi-tractorTractor with an end-dump trailerA FAW semi-trailer truck in China
A semi-trailer truck[1] (also known by a wide variety of other terms – see below) 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.
^"semitrailer". Merriam-Webster. Retrieved 7 February 2022.