sister-in-law

[sis-ter-in-law]

noun

plural

sisters-in-law 

1. the sister of one's spouse.

2. the wife of one's brother or sister.

3. the wife of one's spouse's sister or brother.

sister-in-law

noun

1. the sister of one's husband or wife

2. the wife of one's brother

Word History and Origins

Origin of sister-in-law¹

First recorded in 1400–50; late Middle English syster in lawe; sister, in, law ¹; from Middle English in-lawe “in law,” i.e., “a person within the regulation and protection of the law,” based on the prohibition by Roman civil law and, later, Christian canon law, of marriages within four degrees of consanguinity, i.e., up to and including first cousins

Example Sentences

I learned more from my sister-in-law in Montreal—who made her own baby purées and taught her kids to eat fruit before dessert—than from medical professionals.

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He added that, ahead of winter, the family that includes Umar's parents, a pregnant sister-in-law and small children were now homeless, sheltering in a relative's home.

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She was with her sister-in-law and says they stormed out.

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She was driven from Venice to Riverside by her sister-in-law.

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"My brother's two children were there. Two boys. The elder one passed away, the younger one is missing. My relatives, my sister-in-law, is in the ICU. What should I do?" he said.

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Related Words

• aunt 
• cousin 
• father 
• folk 
• mother 
• niece 
• sibling 
• uncle