The legal definition of a motorcycle for the purposes of registration, taxation and rider licensing in most countries is a powered two-wheel motor vehicle. Most countries distinguish between mopeds up to 49 cc and the more powerful, larger, vehicles known as motorcycles, including scooter type motorcycles.[1] Many jurisdictions include some forms of three-wheelers as motorcycles.
motor scooter n a light motorcycle, usually with small wheels and a curved metal cover at the front to protect the rider's legs
motor scooter n a light motorcycle with small wheels and an enclosed engine. Often shortened to scooter
2. (in full motor scooter) a small-wheeled motorcycle with a protective front shield curving back to form a support for the feet