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Synonyms

sister-in-law

American  
[sis-ter-in-law] / ˈsɪs tər ɪnˌlɔ /

noun

  • sisters-in-law
    plural
  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 British  

noun

  1. the sister of one's husband or wife

  2. the wife of one's brother

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Noun Inflected Forms


Etymology

Origin of sister-in-law

First recorded in 1400–50; late Middle English syster in lawe; see origin at 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

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Rodriguez is survived by his parents, his wife, Sandy, their two sons and his sister-in-law.

From Los Angeles Times ● Oct. 3, 2026

His former sister-in-law told the BBC that she did not know where he was, and nobody had been able to see him.

From BBC ● Sep. 29, 2026

In her “wife school” series, Clark interviewed her new sister-in-law, Katie Voetberg, a prairie dress-clad podcast host and mother of six, about how to avoid being a “nagging wife” and a “constant dripping faucet.”

From Salon ● Sep. 28, 2026

My grandmother now wants to revise her will to include my sister, her five great-grandchildren, my sister-in-law, and me.

From MarketWatch ● Aug. 20, 2026

“So, you’re my sister-in-law now?” said Percy, shaking hands with Fleur as they hurried off toward the staircase with Bill, Fred, and George.

From "Harry Potter and the Deathly Hallows" by J.K. Rowling

BBC Urdu's Tarhub Asghar met two sisters-in-law, both nine months pregnant.

From BBC ● Nov. 1, 2025

She exchanged postcards with former sisters-in-law and her first husband’s second wife.

From Salon ● Feb. 9, 2025

Still, she and her husband and brothers- and sisters-in-law believed that God had a plan for them, even now, she said.

From Los Angeles Times ● Aug. 21, 2023

Stuck, uncomfortably, in the middle, is Sasha, the middle-class New England girl who has married their brother, Cord, and, despite all signs to the contrary, is referred to as “the Gold Digger” by her sisters-in-law.

From New York Times ● Feb. 26, 2023

Patti starts pointing out faces and naming my father's cousins and their sisters and sisters-in-law and brothers and brothers-in-law.

From "Born Behind Bars" by Padma Venkatraman

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