1) 一因いちいん Parts 一 因 #23,982 Link copied! Common いちいん [0] Meaning Shirabe Noun one cause; one reason; one factor 大変たいへんな努力どりょくが彼かれの成功せいこうの一因いちいんであった。 Great effort was one factor in his success. Kanji 一 イチ one, one radical (no.1) 因 イン cause, factor, be associated with Forms 一因#23,982一因いちいんいちいんいちいん