Controlling a tractor with a giant magnet at the tip.
A truck is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile. Commercial trucks can be very large and powerful, and may be configured to mount specialized equipment, such as in the case of fire trucks and concrete mixers and suction excavators.
Modern trucks are largely powered by diesel engines exclusively, although small to medium size trucks with gasoline engines exist in the US. In the European Union, vehicles with a gross combination mass of up to 3,500 kilograms are known as light commercial vehicles, and those over as large goods vehicles.
The word "truck" might come from a back-formation of "truckle" with the meaning "small wheel", "pulley", from Middle English trokell, in turn from Latin trochlea. Another explanation is that it comes from Latin trochus with the meaning of "iron hoop". In turn, both go back to Greek trokhos meaning "wheel" from trekhein. The first known usage of "truck" was in 1611 when it referred to the small strong wheels on ships' cannon carriages. In its extended usage it came to refer to carts for carrying heavy loads, a meaning known since 1771. With the meaning of "motor-powered load carrier", it has been in usage since 1930, shortened from "motor truck", which dates back to 1916.
"Lorry" has a more uncertain origin, but probably has its roots in the rail transport industry, where the word is known to have been used in 1838 to refer to a type of truck, specifically a large flat wagon. It probably derives from the verb lurry of uncertain origin. With the meaning of "self-propelled vehicle for carrying goods" it has been in usage since 1911.
Before that, the word "lorry" was used for a sort of big horse-drawn goods wagon.