Surf is the white, foamy waves that break against the shore. When ocean waves roll toward the beach and crash into shallow water, they create that churning, bubbly water called surf. The bigger the waves, the more dramatic the surf becomes.

The word also describes the sport of riding these waves on a board. Someone who surfs stands or lies on a surfboard and glides along the face of a wave as it moves toward shore. Surfing requires balance, timing, and practice: you have to paddle out past the breaking waves, wait for a good one, then pop up on your board at just the right moment to catch the wave's power.

You'll also hear surf used to mean casually browsing through options. When you surf the web, you click from one website to another without a specific plan, exploring whatever catches your interest. When someone channel surfs, they flip through TV channels looking for something to watch. This meaning comes from how surfers move from wave to wave, always searching for the next good ride. Both kinds of surfing involve moving smoothly through possibilities and seeing what you'll discover.