‘姻娅’ (yīn yà) is a formal, literary term referring collectively to relatives acquired through marriage—such as in-laws, spouses’ siblings and their families, and other kin connected by marital ties. The character 姻 (yīn) means ‘marriage’ or ‘matrimonial relationship’, while 娅 (yà) specifically denotes the sister of one’s spouse (e.g., brother-in-law’s wife or sister-in-law), though in this compound it broadens to encompass the wider network of marital kinship.

This word appears most often in classical texts, formal writing, or respectful speech about family structure—it is rarely used in casual conversation. Unlike colloquial terms like 亲戚 (qīnqi, ‘relatives’) or 亲家 (qìngjia, ‘parents-in-law’), 姻娅 carries a refined, slightly archaic tone and emphasizes the structural bond created by marriage rather than blood ties. It may appear in discussions of traditional clan relationships, genealogies, or social obligations among extended married families.