Dictionary/主因しゅいんShuin主因 (Shuin) is a Japanese noun meaning “primary cause, main factor”.Meaningsnounprimary cause; main factorKanji in 主因主lord因causeRelated words元originご主人your husband原因cause主人head (of a household)主head (of a household)主chief主(one's) master主head (of a household, etc.)因みにby the way主任person in charge死因cause of death由reason