Something, such as a machine or an engine, that produces or imparts motion. A device that converts any form of energy into mechanical energy, especially an internal-combustion engine or an arrangement of coils and magnets that converts electric current into mechanical power. A motor vehicle, especially an automobile: "It was a night of lovers. All along the highway ... motors were parked and dim figures were clasped in revery\u201d ( Sinclair Lewis). Causing or producing motion: motor power. Driven by or having a motor. Of or for motors or motor vehicles: motor oil. Of, relating to, or designating nerves that carry impulses from the nerve centers to the muscles. Involving or relating to movements of the muscles: motor coordination; a motor reflex. To drive or travel in a motor vehicle. To carry by motor vehicle.