sister in law
sister-in-law. The sister of one’s spouse or the wife of one’s brother. • The wife of one’s spouse’s brother is also sometimes considered a sister-in-law. Pl. sisters-in-law.
sister-in-law. The sister of one’s spouse or the wife of one’s brother. • The wife of one’s spouse’s brother is also sometimes considered a sister-in-law. Pl. sisters-in-law.