WHITECAP
whitecap, white horse
(noun) a wave that is blown by the wind so its crest is broken and appears white
Source: WordNet® 3.1
Etymology
Noun
whitecap (plural whitecaps)
Any of several birds having a white patch on the head.
A wave having a white crest; a breaker.
(US, historical) A member of a self-appointed vigilante committee that carried out lynchings. Some early ones wore white hoods or masks.
Source: Wiktionary
White"cap`, n.
1. (Zoöl.)
(a) The European redstart; -- so called from its white forehead.
(b) The whitethroat; -- so called from its gray head.
(c) The European tree sparrow.
2. A wave whose crest breaks into white foam, as when the wind is
freshening.
Source: Webster’s Unabridged Dictionary 1913 Edition