sister-in-law
Americannoun
plural
sisters-in-law-
the sister of one's spouse.
-
the wife of one's brother or sister.
-
the wife of one's spouse's sister or brother.
noun
-
the sister of one's husband or wife
-
the wife of one's brother
Etymology
Origin of sister-in-law
First recorded in 1400–50; late Middle English syster in lawe; see origin at sister, 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.
Standing “square in the doorway like a nightclub bouncer,” Lindsay’s sister-in-law says, “I’m sorry we haven’t got space for you to stay here long term.”
From The Wall Street Journal • May 15, 2026
Another social media user has reported that the textile company where their sister-in-law worked has fired 600 out of their 650 personnel, as they cannot import raw material from Australia anymore.
From BBC • Apr. 21, 2026
Jamshidi has family members, including his brother—who worked in a high-risk post as a security guard for the U.S. consulate in Herat, Afghanistan, for years—his sister-in-law, niece and nephew stuck in Camp As Sayliyah.
From The Wall Street Journal • Apr. 7, 2026
News, which cited emails between Joseph and his sister-in-law Anna Duggar that were exchanged March 21 after Anna and Kendra had spoken.
From Los Angeles Times • Apr. 6, 2026
“My sister-in-law gets me the Hollywood magazines. I just read about it.”
From Full of Beans by Jennifer L. Holm
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
