Noun
The sister of one's husband or wife; also, the wife of one's brother; sometimes, the wife of one's husband's or wife's brother.
Source: Webster's dictionarysister in law
Mo: My sister-in-law had her baby! I'm an aunt! My brother's a father! My mother's a grandma! My dad's a... Sydney: I think I can generalize from there. Alison Bechdel
This show has shown me how to throw a punch. But watching my future sister-in-law go through breast cancer has also shown me how to take one. Charlotte Ross
If the marriage were valid, she'd be your sister-in-law. Cassandra Clare
She is well married who has neither mother-in-law nor sister-in-law. Portuguese Proverb
Well-married is when you have no mother-in-law and no sister-in-law. Spanish Proverb
She is well married who has neither mother-in-law nor sister-in-law. Spanish Proverb