[ sis-ter-in-law ]
/ ˈsɪs tər ɪnˌlɔ /

noun, plural sis·ters-in-law.

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

Origin of sister-in-law

1400–50; late Middle English. See sister, in, law1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for sister-in-law

British Dictionary definitions for sister-in-law


noun plural sisters-in-law

the sister of one's husband or wife
the wife of one's brother
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