surf
n. uncountable A2 Elementary US //ˈsɝf// UK //sˈɜːf// surf
n. the white foam that forms on top of waves as they break on the shore. You can also use it to talk about the area of the ocean where this happens.
n. the mass of white foam formed by waves breaking on a shore or reef. Often used to refer to the zone of water between the shore and the breaking waves.
The children played in the white surf all afternoon.
The sound of the crashing surf made it difficult to hear the conversation on the beach.
Experienced swimmers know that the pull of the receding surf can be deceptively strong, even when the waves appear manageable from the safety of the dunes.
Usage
Usually takes the definite article 'the' when referring to the physical water at the beach.