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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:

“One of Us” is about your brother-in-law, which made me realize how few people write songs about their in-laws.

From Los Angeles Times ● Oct. 9, 2026

"It's a nice little story being able to say we played rugby against Taylor Swift's brother-in-law, which I'm sure he loves as a title," Hackney full-back Peter Scott joked to BBC Sport.

From BBC ● Oct. 9, 2026

The project’s masonry contractor was a firm called Acranom, whose vice president, John Duffy, was Diamantis’s former brother-in-law and called him “Uncle.”

From The Wall Street Journal ● Oct. 8, 2026

When Min came down with Stage 4 colorectal cancer a few years ago, his sister and brother-in-law were a constant presence at his side.

From Los Angeles Times ● Oct. 4, 2026

Even after Shady’s comment about Sheriff Dean and his sheriff brother-in-law in Joplin, Jinx felt strangely at ease and comforted as they made their way back to Shady’s place.

From "Moon Over Manifest" by Clare Vanderpool

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

“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

The duo, who were brothers-in-law, merged into a single enterprise in 1958.

From Los Angeles Times ● Mar. 3, 2023

If your better half has two brothers, are they your brothers-in-law or your brother-in-laws!

From "Woe Is I" by Patricia T. O'Conner

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