A humain propelled vehicle with one wheel. Usually, unicycles have pedals, cranks, and seats derived from regular two-wheeled bicycles. Having been around for years as props for entertainers, they are comming back now as a proper form of transportation and recreation. Popular with people with certain mental conditions. Usually refered to as a "Uni". (also see Muni, Coker} and Trials Uni.
That crazy bastard is going down the mountain with his unicycle!
A unicycle with a very large wheel diameter, used in long distance riding. The bigger wheel gives the unicycle the ablility to move over great distances in relativily short periods of time, while still amazing everone who sees it.
A unicycle which is used for hopping, jumping, or riding over various obstacles. Usually has a smaller wheel then a normal unicycle, and stronger components to take extra punishement. In use, the rider hops the trials unicycle over rocks, barriers, curbs, ramps, or wooden pallets. Might also be referred to as a Tuni, but the name has never become popular.