noun, plural broth·ers-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.

Nearby words

  1. brothel,
  2. brother,
  3. brother jonathan,
  4. brother of the christian schools,
  5. brother's keeper, am i my,
  6. brotherhood,
  7. brotherliness,
  8. brotherly,
  9. brothers karamazov, the,
  10. brotula

Origin of brother-in-law

Middle English word dating back to 1250–1300 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for brother-in-law

British Dictionary definitions for brother-in-law


noun plural 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

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