sister-in-law
Americannoun
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the sister of one's spouse.
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the wife of one's brother or sister.
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the wife of one's spouse's sister or brother.
noun
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the sister of one's husband or wife
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the wife of one's brother
Other Word Forms
Noun Inflected Forms
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.
See Examples For:
When they caught wind of the mysterious suitor, Danielle’s mom, sister and sister-in-law each found his LinkedIn page.
From The Wall Street Journal ● Jul. 1, 2026
"We have already lost our mother and sister-in-law who was married to my brother who is here. We have mourned a lot. We don't want to mourn any more," he told the BBC.
From BBC ● Jun. 15, 2026
Her sister-in-law, Millicent Sedra, also spoke and scolded women who expect husbands to share housework.
From Salon ● Jun. 12, 2026
Kym and sister-in-law Kirsten Swanson McGillicuddy, flew out to join the search but it was put on hold due to treacherous weather conditions.
From BBC ● Jun. 4, 2026
My Aunt Libby had married an Italian, and Teresa was my aunt's sister-in-law and our family doctor.
From "The Bell Jar" by Sylvia Plath
She exchanged postcards with former sisters-in-law and her first husband’s second wife.
From Salon ● Feb. 9, 2025
Still, she and her husband and brothers- and sisters-in-law believed that God had a plan for them, even now, she said.
From Los Angeles Times ● Aug. 21, 2023
I saw my wife and one of my sisters-in-law being swept away, followed by my elder brother.
From BBC ● Jun. 15, 2023
Moreno's wife, one of their daughters, two of his brothers and two sisters-in-law are also among those allegedly connected to the case, Salazar said.
From Reuters ● Feb. 22, 2023
Patti starts pointing out faces and naming my father's cousins and their sisters and sisters-in-law and brothers and brothers-in-law.
From "Born Behind Bars" by Padma Venkatraman
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.
