noun
northern waters; northern seas
Refers to the seas or ocean areas in the north, often used in contexts like fishing, shipping, or geography (e.g., 北洋漁業, northern-sea fisheries).
北洋サケ漁が解禁された。
The northern salmon fishery has opened.
北洋の荒波を越えて船は進んだ。
The ship sailed through the rough seas of the north.