Try Our Apps


90s Slang You Should Know


[bruhth -er-in-law] /ˈbrʌð ər ɪnˌlɔ/
noun, plural brothers-in-law.
the brother of one's husband or wife.
the husband of one's sister.
the husband of one's wife's or husband's sister.
Origin of brother-in-law
Middle English word dating back to 1250-1300 Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
Cite This Source
Examples from the Web for brother-in-law
Contemporary Examples
Historical Examples
  • It is undoubtedly my brother-in-law's last will and testament, and, as far as I can see at a glance, it is altogether regular.

    Cousin Henry Anthony Trollope
  • One winter day Boone and his brother-in-law were captured by Indians.

    Daniel Boone Katharine E. Wilkie
  • In three nights he promoted the Count of Vendome from a fresh acquaintance to a schoolmate, and then brother-in-law.

  • Her brother-in-law regarded her thoughtfully through his eye-glasses.

    Emmy Lou George Madden Martin
  • Do you mean my brother-in-law will refuse to help me if my daughter does not go to manage his house?

    A Crooked Path Mrs. Alexander
British Dictionary definitions for brother-in-law


noun (pl) brothers-in-law
the brother of one's wife or husband
the husband of one's sister
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
Cite This Source
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."

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source

Word of the Day

Difficulty index for brother-in-law

Few English speakers likely know this word

Word Value for brother

Scrabble Words With Friends

Nearby words for brother-in-law