Small used car lot in the United States.

Typical new car dealership selling used cars outside the showroom.

An auto mechanic (or car mechanic in British English and motor mechanic in Australian English) is a mechanic who specializes in automobile maintenance, repair, and sometimes modification. An auto mechanic may be knowledgeable in working on all parts of a variety of car makes or may specialize either in a specific area or in a specific make of car. In repairing cars, their main role is to diagnose the problem accurately and quickly. They often have to quote prices for their customers before commencing work or after partial disassembly for inspection. The mechanic uses both electronic means of gathering data as well as their senses. Their job may involve the repair of a specific part or the replacement of one or more parts as assemblies.

A mechanic working on the differential of a car

A road tractor coupled to a semi-trailer is often called a semi-trailer truck or semi, or in the UK an articulated lorry.

In Australian English, the tractor unit is usually referred to as a prime-mover; and the combination of a prime-mover and trailer is known as a semi-trailer or semi. Semi-trailers with two trailer units are B-Doubles or road trains. A B-double consists of a prime mover towing two semi-trailers, where the first semi-trailer is connected to the prime mover by a fifth wheel coupling and the second semi-trailer is connected to the first semi-trailer by a fifth wheel coupling. A road train means a combination, other than a B-Double, consisting of a motor vehicle towing at least two trailers (counting as a single trailer a converter dolly supporting a semi-trailer).

A tractor unit pulling a semi-trailer

A truck pulling a semi-trailer using a trailer dolly

 

From Wikipedia, the free encyclopedia : Trade in cars and trailers, possibly combined with repair