Author: Jim C. (---.208.238.244.LosAngeles.Level3.net)
Date: 10-18-00 00:31
Moped: A two or three wheeled vehicle other than a tractor having an engine of no more than 2HP and an automatic transmission and maximum speed of 30MPH having pedals for propulsion.
That's the California definition and pretty much complies with the Federal (USA) description.
So in a nutshell: Pedals, 2HP max, 30MPH max, no gearshift.