Semi-trailer truck
（重定向自Eighteen Wheeler）
![Semi-trailer tractor with sleeper behind the cab and oversize load on lowboy trailer](/Images/godic/202501/10/Backing_it_in_23741.jpg")
![A tractor with an auto-transport semi-trailer](/Images/godic/202501/10/Truck.car.transporter.arp.750pix3741.jpg")
![FAW semi-trailer truck in China](/Images/godic/202501/10/FAW_truck3741.jpg")
![Tractor unit hauling tractor units in Idaho](/Images/godic/202501/10/HuckepackCrop3742.JPG")
A semi-trailer truck is the combination of a tractor unit and one or more semi-trailers to carry freight. It is variously known as a transport (truck) in Canada; semi or single in Australia; semi, tractor-trailer, big rig, or eighteen-wheeler in the United States; articulated lorry, abbreviated artic, in Britain and Ireland.