HyperDic: head_sea

English > 1 sense of the expression *head sea*:
NOUN	phenomenon	head sea	a sea in which the waves are running directly against the course of the ship

English > *head sea*: 1 sense > noun 1, phenomenon
Meaning	A sea in which the waves are running directly against the course of the ship.
Broader	sea	turbulent water with swells of considerable size