A rare standalone noun for the top or projecting part of the head. Modern learners will most often see it inside the idiom 頭角を現す, literally involving 頭角 but used idiomatically for someone beginning to stand out.
See also: 頭角を現す
Literally, 頭角 refers to the top of the head, but in modern Japanese it is not often used by itself.
She began to stand out from her first year at the company.