The closest term to what I want to know is, so far, 'Swash'. But not exactly, because it is a term for 'wave' not ...the foam/the frothy part of the wave. I want to know if there is a term for that white part of the swash. Like, when a wave gently breaks on the shore or hits with a rock and then there's the white froth happening. I'm sorry I feel like I am rambling now; (Or...maybe Whitecapping? But it seems to me that is also just a description of another wave form, bah..)
"Foam" is the simplest word to use, "Ocean foam" or "Sea foam" if the context doesn't allow the word "sea" to be dropped.
Two boys were playing in the foam on the beach.
Foam produced on waves far from the beach by strong winds are called "White horses"
The wind picked up in the afternoon, and the sea became covered in white horses.
I don't know what is really going on within the OP's mind (Ugh sorry). but it is definately the Sea Foam.
Please refer to the Wiki page, I can not say anymore.
Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater,