Well, it is a sport that takes place on the water's surface when a wave carries the rider toward shore
It's a sport that takes place on the water's surface when a wave carries the rider toward shore on a surf board
How do you define surfing?
Surfing is a surface water sport in which the wave rider, referred to as a surfer, rides on the forward or deep face of a moving wave, which is usually carrying the surfer towards the shore.