安全期[anzenki] safe period
暗黒期[ankokuki] eclipse period
一期[ichigo] one's life time
一期[ikki] one term
一期一会[ichigoichie] once-in-a-lifetime encounter (hence should be cherished as such)

一周期[isshuuki] period (in astronomy)
一定期間[itteikikan] fixed interval
延期[enki] postponement
延期になる[enkininaru] to be postponed
沖積期[chuusekiki] alluvial period

易経[ekikyou] I Ching (Yi Jing) or The Book of Changes - one of the Five Classics
一切経[issaikyou] complete Buddhist scriptures
運動神経[undoushinkei] motor nerves
規模の経済[kibonokeizai] economies of scale
共同経営[kyoudoukeiei] joint management

経つ[tatsu] to pass
経る[heru] to pass
経緯[ikisatsu] details
経営[keiei] management
経営グループ[keieiguruupu] management group

開け閉て[aketate] opening and shutting
開閉[kaihei] opening and shutting
基地閉鎖[kichiheisa] (military) base closing
自閉症[jiheishou] autism
腸閉塞[chouheisoku] intestinal obstruction

閉まる[shimaru] to be shut
店閉まい[misejimai] closing up shop
閉ざす[tozasu] to shut
閉じる[tojiru] to close (e.g. book, eyes, meeting, etc.)
閉込める[tojikomeru] to lock up