A longboard is a surfing variant of a skateboard, similar and related to a surfboard or snowboard with wheels.
It is used for cruising, downhill racing, sliding, and transport. However, most stunts, and the boards themselves are very different from that of a typical skateboard.
They usually are designed for the descent of a hill, slides, carves, manual or "dancing" with the board. The first longboard was invented by Tyler Danger Gronseth. He used a tree he cut down by hand, a pair of skateboard trucks and wheels, and some rusty nails.
The Longboard Store, TLS, Landyachtz.
Wikipedia, "Longboard (skateboard)",