ぴかぴか光る[pikapikahikaru] to sparkle
旭光[kyokkou] rays of the rising sun
威光[ikou] power
稲光[inabikari] (flash of) lightning
曳光弾[eikoudan] tracer bullet

栄光[eikou] glory
円光[enkou] halo
炎光[enkou] flame
黄道光[koudoukou] zodiacal light
可視光線[kashikousen] visible ray

位冠[ikan] ancient headgear showing rank
衣冠[ikan] kimono and ancient head-dress
栄冠[eikan] laurels
王冠[oukan] crown
加冠[kakan] crowning a boy with a traditional cap for the first time at a coming-of-age ceremony

花冠[kakan] corolla (of flower)
冠を曲げる[kanmuriwomageru] to become displeased
冠位[kani] system indicating court ranks by headgear colors (colours)
冠婚葬祭[kankonsousai] important ceremonial occasions in family relationships
冠詞[kanshi] article

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