wave
Undulation caused by the wind on the surface of a sea or lake.
wave base 
Maximum depth beneath which wave action is no longer perceptible.
still water level 
Level of the water surface in the absence of waves.
trough 
Lowest point of the wave.
sand bar 
Accumulation of sediment at the bottom of the sea, close to the shoreline; it is sometimes exposed at low tide.
foam 
Whitish froth that forms on the water surface when a wave breaks.
shore 
Strip of land where the sea meets the land.
breaker 
High wave that breaks on the coast.
wave length 
Horizontal distance between two successive crests or troughs.
crest 
The highest point of a wave.
wave height 
Vertical distance between the crest and the trough.