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

悪循環[akujunkan] vicious circle
一環[ikkan] link (e.g. a part of a larger plan)
印環[inkan] signet ring (in medical contexts, e.g. signet ring cell)
円環[enkan] circle
花環[hanawa] wreath

環境[kankyou] environment
環境グループ[kankyouguruupu] environmental group
環境事業[kankyoujigyou] environmental business
環境庁[kankyouchou] Environment Agency
環境庁長官[kankyouchouchoukan] Director General of Environment Agency