海峡[kaikyou] channel (e.g. between two land masses)
峡谷[kyoukoku] glen
峡部[kyoubu] isthmus
峡湾[kyouwan] fjord
山峡[sankyou] gorge

台湾海峡[taiwankaikyou] Straits of Taiwan
地峡[chikyou] isthmus
間宮海峡[mamiyakaikyou] strait between Sakhalin and the east coast of Siberia
英仏海峡[eifutsukaikyou] the English Channel
峡間[kyoukan] between the mountains

海鷂魚[ei] ray (fish)
井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
一天四海[ittenshikai] the world
雲海[unkai] sea of clouds
沿海[enkai] coast

遠海[enkai] deep sea
黄海[koukai] Yellow Sea
温海[atsumi] warm sea
海の幸[uminosachi] seafood