A coachbuilder is a person or a firm that builds the outer body of a vehicle — the shell you see, the doors, the roof — rather than the engine or the frame underneath. The “coach” here is the old word for a carriage, the kind horses pulled, and then for the body of a car. In the early days of cars, one company might make the chassis (the bones and the engine) and a coachbuilder would put a special body on top: a long elegant car, a hearse, an open-top car. You still hear coachbuilt for a car whose body was made that way, often by hand and at high cost. Though actually this is not a sports coach, and it is not someone who “builds” a team. It is a craft job from the carriage trade that moved into cars.

車身打造師傅、車體廠。這裡的 coach 是馬車／車身，不是運動教練。