What is a 18 wheeler truck called?

The most common name for an 18-wheeler truck is a semi-trailer truck. Here’s a breakdown of the term and its components:

  • Semi-trailer: This refers to the trailer part of the vehicle. It has wheels only at the rear and connects to the front of the truck using a coupling mechanism called a fifth wheel. The trailer itself does not have a steering mechanism and relies on the truck to maneuver.
  • Truck: This refers to the tractor unit that pulls the semi-trailer. It has a cab for the driver, an engine, and front wheels for steering.

Therefore, “semi-trailer truck” accurately describes the combination of a tractor unit and a semi-trailer, which is the defining characteristic of an 18-wheeler.

Here are some other terms you might encounter for an 18-wheeler truck:

  • 18-wheeler: This term is widely used and easily understood, but it’s a bit informal.
  • Big rig: This is another informal term, often used in North America, to describe large trucks, including 18-wheelers.
  • Tractor-trailer: This term is also accurate, but it can also refer to any combination of a tractor unit and a trailer, not just an 18-wheeler specifically.

It’s important to note that the number of wheels doesn’t necessarily define the type of truck. While many 18-wheelers have 18 wheels (six wheels on the tractor and 12 on the trailer), some might have more or fewer wheels depending on the specific configuration and purpose.