Cosisterinlaw

Cosisterinlaw, also spelled co-sister-in-law or cosister-in-law, is a kinship term used to describe a specific in-law relationship. It refers to the wife of one's husband's brother. In families where two brothers marry two sisters, the two wives are considered co-sisters-in-law to each other. The term is most commonly encountered in South Asian English-language usage, though it appears in broader discussions of kinship terminology as well.

Usage and variations: The term can be written in several forms, including cosisterinlaw, co-sister-in-law, and cosister-in-law. The more common English spelling is co-sister-in-law. Usage varies by community, and some speakers may simply refer to the person as “my sister-in-law” unless a more specific designation is needed.

Context and nuance: Like other in-law terms, cosisterinlaw denotes a familial relationship that is created through marriage, not blood. Its exact connotations can be culturally nuanced and gender-specific, often reflecting the social dynamics of extended families. Some contexts may emphasize cordiality or hierarchy, while others treat the relationship as a practical family connection without strong formal roles.

Example: If A is married to B, and B has a brother C who is married to D, then D is A’s cosisterinlaw; correspondingly, A and D are often described as co-sisters-in-law.