Why Is A Truck Called A Semi?

If you’re wondering why large, boxy vehicles are always referred to as ‘semi-trucks,’ have you ever noticed the unmistakable ‘semi’ attached to the back or side of the truck? Put simply, ‘semi’ refers to the fact that the truck only has one half of the powertrain attached. Both tractors and trailers have their own powertrains, which explains why they are the perfect combination for heavy hauling jobs.

So, now that you understand the historical origin of the term, let’s explore a little more about why these vehicles are so important in the transportation industry and the regulations surrounding them.

Why Is a Truck Called a Semi?

Semi-trucks, also called semi-trailers or semis, are large and important vehicles that many companies and individuals use for shipping across the United States and the world.

Many people drive or ride in these types of trucks, but few people know why they’re called semi-trucks. Knowing the simple explanation behind this word is important not only to appreciate the truck name but also to understand the industry better.

Origins of “Semi-Truck”

The origin of the word “semi-truck” dates back to the late 1920s when the first semi-trailers were created.

In these early years, semi-trailers were different from the standard wagon, or horse-drawn and powered, freight haulers in one major way: the presence of a cab for the driver and not the cargo. These cabs, known as semi-cabs, eventually became the defining feature of what we now call semi-trucks with the final term “semi” coming from the combination of two words: semi-trailer and truck cab. The final result of this combo, “semi-truck,” has been commonly used since the 1940s and likely originated in the United States.

Semi-Trucks vs. Full-Trailers

Today, the main difference between a semi-truck and a full-trailer, the two types of freight haulers, is the presence or absence of the semi-cab.

Where the semi-truck is attached to the cab, the full-trailer, sometimes called a tractor-trailer, is made from the combination of one box-shaped trailer attached to the cab. Because full-trailers do not have the semi-cab, drivers can close them with a tailgate or curtains for added security.

Benefits of Semi-Trucks

Semi-trucks have several advantages over full-trailers. First, they are able to hold more cargo than full-trailers, making them more convenient for transportation companies. Second, their cab makes them more roadworthy; because the cab sits on top of the trailer, the weight of the cargo is spread out more evenly, allowing semi-trucks to last longer and turn more easily.

Lastly, because of their length and size, semi-trucks are able to take on multiple shipments at once, making them more cost-effective and efficient.


In conclusion, semi-trucks are large, important road vehicles that have been used to transport items and goods around the world for decades. Though the exact origin of the term “semi-truck” is unknown, it’s clear that the vehicle gets its namesake from the early semi-trailers and trucks. Additionally, semi-trucks today hold advantages over full-trailers because of their cab, size and weight distribution. Citation URL: https://transval. com/what-is-a-semi-truck/https://www. mcmillen-trucking. com/what-is-the-difference-between-a-semi-truck-and-a-full-trailer/ https://en. wikipedia. org/wiki/Semi-trailer_truck

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