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Synonyms

brother-in-law

American  
[bruhth-er-in-law] / ˈbrʌð ər ɪnˌlɔ /

noun

  • brothers-in-law
    plural
  1. the brother of one's spouse.

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

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


brother-in-law British  

noun

  1. the brother of one's wife or husband

  2. the husband of one's sister

  3. the husband of the sister of one's husband or wife

"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 brother-in-law

First recorded in 1350–1400; Middle English brother in law(e); see origin at brother, 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:

Jung Da-kyung, a law student, recalls a female friend asking her brother-in-law, an SK Hynix employee, to be introduced to someone at the chip maker.

From The Wall Street Journal Aug. 10, 2026

The 64-year-old billionaire and head of African football has been repeatedly mentioned in the South African media as a potential successor to his brother-in-law, President Cyril Ramaphosa, whose second and final term ends in 2029.

From Barron's Jul. 22, 2026

Daniel Powers, Cancro’s brother-in-law, got around $30 million at that time, while Phillip Sivolobov, Cancro’s stepson, received total compensation of approximately $50 million.

From MarketWatch Jul. 2, 2026

Word spread that Sillie’s missing brother-in-law had sent a cellphone text message: “We are trapped, help.”

From Los Angeles Times Jun. 30, 2026

It turned out the SIM agent in charge recognized Tío Pepe, whose brother-in-law, Dr. Mella, had saved his little daughter’s life after a ruptured appendix.

From "Before We Were Free" by Julia Alvarez

During the Civil War her brother George was a surgeon at a Confederate hospital, while three half-brothers and four brothers-in-law all supported the Confederacy.

From The Wall Street Journal May 11, 2026

The two, once active in rival North Hollywood gangs, sat at a elegant desk built by Tejada’s brothers-in-law.

From Los Angeles Times Oct. 29, 2024

“Do you know what forces us to get in there?” said Margara Sanchez, whose brothers-in-law, uncles and cousins work at the mine.

From Seattle Times Feb. 22, 2024

Urfan's Pakistan-based family have taken Jhelum police to court twice, accusing them of detaining several of Urfan's brothers and brothers-in-law illegally.

From BBC Sep. 5, 2023

One of my brothers-in-law was a roofing foreman.

From "Farewell to Manzanar" by Jeanne Houston

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