A skateboard is typically a specially designed plywood board combined with a poly urathane coating used for making smoother grinds and stronger durability, used primarily for the activity of skateboarding.
It appears the first skateboards to reach public notice came out of the surfing craze of the early 1960's, probably just wooden boards with roller-skate wheels attached. The surfing group Jan and Dean even had a minor hit called "Sidewalk Surfing" in 1964. The modern skateboard originated in California in the 1970s with the advent of Polyurethane wheels. In time, it became a pastime for surfers when the waves were lax. By the mid 1980s they were mass produced and sold throughout the United States.