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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

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

In the days before her death, Tracey Davies told her sister-in-law she believed Davies was having "some sort of breakdown".

From BBC ● Sep. 11, 2026

She was also Chiang’s sister-in-law, and though the two shared few political convictions, the family connection protected Soong even though she supported the couple.

From The Wall Street Journal ● Aug. 28, 2026

“You can’t have a daughter, since you abandoned her when she was little and went to war,” the sister-in-law argued.

From "A Thousand Sisters" by Elizabeth Wein

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

From Salon ● Feb. 9, 2025

"My father, my brother, my sisters-in-law and my friends are gone," says Delfino.

From BBC ● Feb. 7, 2025

His mother was ill, so one of her sisters-in-law filled out the registration card and submitted it to the city to produce a birth certificate, Didier Optowsky said.

From Los Angeles Times ● Apr. 26, 2024

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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