a powerful motor-driven vehicle with large, heavy treads, used for pulling farm machinery, other vehicles, etc.

Also called truck tractor. a short truck with a driver's cab but no body, designed for hauling a trailer or semitrailer.

something used for drawing or pulling.

Aeronautics .

a propeller mounted at the front of an airplane, thus exerting a pull.

Also called tractor airplane. an airplane with a propeller so mounted.