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Synonyms

mother-in-law

American  
[muhth-er-in-law] / ˈmʌð ər ɪnˌlɔ /

noun

  • mothers-in-law
    plural
  1. the mother of one's spouse.


mother-in-law British  

noun

  1. the mother of one's wife or husband

"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

Other Word Forms

Noun Inflected Forms

Etymology

Origin of mother-in-law

First recorded in 1350–1400; Middle English moder in lawe; see origin at mother 1 ( def. ), in ( def. ), law 1 ( def. ); 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:

My mother-in-law died several years ago, leaving her longtime residence as part of her estate.

From MarketWatch ● Sep. 24, 2026

Debu Sapkota, a 58-year-old driver, came to post photos of his 83-year-old mother-in-law and her granddaughter who went missing in the town of Trishuli Bazaar after being swept away by last week's surge.

From Barron's ● Sep. 1, 2026

And I never saw this coming: She became my mother-in-law.

From Los Angeles Times ● Aug. 28, 2026

Molly signed up for an Elite Caribbean cruise with her mother in February, also taking her husband and mother-in-law.

From The Wall Street Journal ● Aug. 27, 2026

The Duke, for reasons passing understanding, next became smitten with his very own mother-in-law, which caused the Duchess ulcers, only they didn’t have ulcers yet.

From "The Princess Bride" by William Goldman

They teased one another, complained about overbearing mothers-in-law and celebrated milestones, like a daughter’s quinceañera.

From Los Angeles Times ● Nov. 30, 2025

No one today any longer wishes to hear jokes about nagging mothers-in-law, spendthrift wives or old jalopies, and the men and women who once told them to hardy plaudits are now forgotten.

From The Wall Street Journal ● Nov. 14, 2025

Lila Charif, Bahar Tavakolian and Laya Kadjavi, whose mothers and mothers-in-law were also close to mine, drew much inspiration from her in their own cooking.

From Salon ● Sep. 15, 2024

There, a team led by medical anthropologist Adelaide Lusambili of Africa International University conducted interviews with dozens of pregnant women, new mothers, male partners, mothers-in-law, community health care workers, and community leaders in 2021.

From Science Magazine ● Sep. 27, 2023

They had all brought their mothers-in-law and children, and even their village friends who were not lucky enough to have overseas Chinese relatives to show off.

From "The Joy Luck Club" by Amy Tan

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