<p><strong>Noun:</strong></p><ul><li>A device for riding upon, usually while standing, consisting of a short, oblong piece of wood, plastic, or metal mounted on large roller-skate wheels, used on smooth surfaces and requiring better balance on the part of the rider than ordinary roller skates do: Skateboards were pretty “primitive” back in the sixties.</li></ul><p><strong>Noun (Plural):</strong></p><ul><li>One of a pair of long, slender runners made of wood, plastic, or metal used in gliding over snow.</li><li>Water ski.</li></ul><p><strong>Verb:</strong></p><ul><li>(Used without object) To travel on skis, as for sport.</li><li>(Used with object) To use skis on; travel on skis over: to ski the slopes of Switzerland.</li></ul>