Dinky little motorcycle, usually with an engine below 125 cc. Smaller than a scooter. In some cases it looks like a clumsy bycicle with a motor tacked on. One prime example is the Ciao, but Peugeot has many models as well.
I suspect this to be a British word. Anyway, the mopeds are almost absent in the US, and very present in Europe and Asia. For example, Bamako is positively infested with them.

A moped has an under 50cc engine, pedals, large tires, and goes under 30mph usually. Anything else is a scooter or a motorcycle. Spree's and Razz's are not mopeds.

They are very popular forms of transportation outside of the United States, but a small resitance group is forming to bring them back in popularity and help them achieve the respect they are due. This group is the Moped Army

Types of mopeds include:

Batavus, Crescent, Derbi, Garelli, Hercules, Hero-Majestic, Honda, Jawa, Kinetic, Kreidler, Motobecane, Pacer, Peugeot, Piaggio, Puch, Sachs, Suzuki, Tomos, Vespa, Yamaha, VeloSolex, Whizzer, Zundapp, AMF, Angel, Milani, Cimatti, Typhoon, Phillips, Gizmo, Binachi, Allstate, Ariel, Sears, JC Penny, Benelli, Gloria Intramotor, Indian, Snark, Solex, Harley, Concord, Columbia, Husqvarna, Korado, Riga, Bajaj, Califo, Rizzato, Odyssey, Malanca.

One day may the streets be filled with the roaring of 50cc engines and the highways be too clogged for bloated four wheelers to travel on. We will enjoy the beauty of the moped, and its adherence to friendly travel, easy stop communication, and the ability to enjoy the trip - as well as the destination.

2-Stroke Power. Swarm and Destroy. Moped Army