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See more synonyms for brother-in-law on Thesaurus.com
noun, plural broth·ers-in-law.
  1. the brother of one's husband or wife.
  2. the husband of one's sister.
  3. the husband of one's wife's or husband's sister.
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Origin of brother-in-law

Middle English word dating back to 1250–1300
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for brother-in-law

Contemporary Examples

Historical Examples

  • I suppose he'll be a little more fastidious, as the brother-in-law of Shepler.

    The Spenders

    Harry Leon Wilson

  • He cut off my brother-in-law's leg—charged him as much as if he had grown a new one for him.


    Mary Roberts Rinehart

  • Mrs. MacDermott almost shouted the words at her brother-in-law.

    The Foolish Lovers

    St. John G. Ervine

  • And, moreover, his wife was in charge of his brother-in-law.

    The Secret Agent

    Joseph Conrad

  • He looked dubiously at his brother-in-law, but he did not ask him for information.

    The Secret Agent

    Joseph Conrad

British Dictionary definitions for brother-in-law


noun plural brothers-in-law
  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
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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

Word Origin and History for brother-in-law


c.1300; also brother in law; see brother. In Arabic, Urdu, Swahili, etc., brother-in-law, when addressed to a male who is not a brother-in-law, is an extreme insult, with implications of "I slept with your sister."

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Online Etymology Dictionary, © 2010 Douglas Harper