A motor scooter is a motorcycle similar to a kick scooter with a seat, a floorboard, and small or low wheels. The United States Department of Transportation defines a scooter as a motorcycle that has a platform for the operator's feet or has integrated footrests, and has a step-through architecture.
The classic scooter design features a step-through frame and a flat floorboard for the rider's feet. This design is possible because most scooter engines and drive systems are attached to the rear axle or under the seat. Unlike a conventional motorcycle, in which the engine is mounted on the frame, most modern scooters allow the engine to swing with the rear wheel, while most vintage scooters and some newer retro models have an axle-mounted engine.