‘姨舅’ (yí jiù) is a compound kinship term referring specifically to the husband of one’s maternal aunt — that is, the man married to one’s mother’s sister. The first character 姨 (yí) means ‘maternal aunt’, and the second 舅 (jiù) means ‘maternal uncle’, but in this fixed compound, 舅 shifts meaning to denote ‘husband’ (a rare, archaic usage). This term is not standard in modern Mandarin; it appears mainly in certain southern dialects or older literary texts and is rarely used in everyday speech.

In contemporary Chinese, people almost always say ‘姨父’ (yí fù) instead — literally ‘aunt-father’, the respectful, widely understood term for the same relationship. ‘姨舅’ may cause confusion among native speakers outside specific regional contexts, and learners should treat it as a lexical curiosity rather than a functional vocabulary item for daily communication.