(geography) North Pole, the Arctic

a sea, an ocean / a lake / (figuratively) an object covering over a large area, as in 血の海 (chi no umi, “pool of blood”) or 火の海 (hi no umi, “sea of fire”)

(ecology) habitat

(mathematics) singularity; singular point

oceanography

Kyūjitai form of 海洋学: oceanography

marine pollution

sea, ocean / vastly gathered / large, wide

a female given name

of the sea, of the ocean