A scooter is a style of two wheeled motor vehicle with certain design characteristics such as a step-through frame, small wheels, automatic transmission and small engine. The general definition of a scooter is evolving as motorcycle designs have changed over time. Historically, a scooter was noted for a small engine, small wheels, a step-through design, a forward fairing with floorboards, and possibly under-seat storage. Modern scooters cover a broad spectrum of cycle design: step-through design or step-over design, small or large wheels, front fairings or floor boards, under-seat storage or not, and manual or automatic transmissions. Most scooters today feature automatic transmissions.
At one end of the current market, the Vespa LX series reflects the scooters' historical antecedents: small-wheeled, floor boards, front fairing, inner fairing storage. Though still was classified as a scooter. The Piaggio MP3, with two front wheels (three wheels total) reflects the fluid nature of the scooter classification. Modern scooters have a wide range of engine displacements from under 50 cc to over 799 cc, and some have engine locations in stark contrast to classic scooter design (e.g. Yamaha T-Max 500, Suzuki Burgman 650, Gilera GP800).
Generally the term "scooter" is not defined in law, as scooters are a style of motorcycle and laws are based on characteristics such as engine size and power, and maximum speed. Defines a scooter as having a platform for the operator's feet or has integrated footrests, and has a step-through architecture.