A wave with little or no downward-sloping angle along the crest. Although a "walled up" or "walled off" wave is synonymous with a "closeout" and no good for board-surfing, the expression "wall" is also used to describe a wave that appears to be a closeout, but in fact holds shape. Some of the world's best waves—including Laniakea, Rincon, and Jeffreys Bay—are described as having "long walls."