adj. designed for or used for or taking place on trails and beaches etc., instead of public roads; as, off-road vehicles; off-road sports such as snowmobiling. [ Narrower terms: cross-country (vs. road) ] [ WordNet 1.5 ]
n. a bicycle with a sturdy frame and fat tires; originally designed for riding in mountainous country; amountain bike. Syn. -- mountain bike, all-terrain bike. [ WordNet 1.5 ]