sis·​ter | \ ˈsi-stər How to pronounce sister (audio) \

Definition of sister

1 : a female who has one or both parents in common with another

2 often capitalized

a : a member of a women's religious order (as of nuns or deaconesses) especially : one of a Roman Catholic congregation under simple vows
b : a girl or woman who is a member of a Christian church
3a : a girl or woman regarded as a comrade
b : a girl or woman who shares with another a common national or racial origin especially : a black girl or woman
4 : one that is closely similar to or associated with another sister cities
5 chiefly British : nurse
6a : girl, woman
b : person usually used in the phrase weak sister
7 : a member of a sorority

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Examples of sister in a Sentence

The sisters live in the convent.

Recent Examples on the Web

Friends and classmates said that Crusius — who has an older brother in addition to his twin sister — grew up as a somewhat odd, lonely boy who loved snakes and playing video games such as Halo. Washington Post, "As his environment changed, suspect in El Paso shooting learned to hate," 10 Aug. 2019 She was preceded in death by her husband, John E. Baldwin and her sister, Violet Rycroft., "Deaths in South Florida: 8/9," 9 Aug. 2019 The shooter who murdered nine people, including his sister, in Dayton was killed by police officers on patrol after 30 seconds of mayhem. The Economist, "Politics this week," 8 Aug. 2019 Our top story today comes from USC, where offensive lineman Austin Jackson has rejoined the team after donating bone marrow to his little sister, who suffers from a rare genetic disorder. Jon Wilner, The Mercury News, "Hotline newsletter: Top basketball prospects in class of 2020 considering Pac-12 programs," 7 Aug. 2019 In Dayton, police say a man shot and killed nine people, including his sister, in a nightlife district early Sunday. Jason Hanna, CNN, "CNN will host a town hall on gun violence Wednesday night," 7 Aug. 2019 Barbara Pierce Bush Coyne certainly knows the way to her twin sister Jenna Bush Hager and her newborn nephew’s heart: donuts and tacos! Joelle Goldstein,, "Jenna Hager Bush's Newborn Son Gets His First Visitor Who Comes Bearing a Delicious Surprise," 6 Aug. 2019 Still unknown is whether Betts targeted any of the victims , including his 22-year-old sister, Megan, the youngest of the dead. John Seewer, Fortune, "Republican Governor Calls for Gun Sale Background Checks After Ohio Shooting," 6 Aug. 2019 To celebrate the occasion, Jenna's whole family came to visit to her at the hospital, including her sister, Barbara, who brightened up her day even more with a big box of donuts. Kayla Keegan, Good Housekeeping, "'Today' Star Jenna Bush Hager Reveals the Emotional Meaning Behind Her Son's Name," 5 Aug. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sister.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sister

before the 12th century, in the meaning defined at sense 1

History and Etymology for sister

Middle English suster, sister, partly from Old English sweostor and partly from Old Norse systir sister; akin to Latin soror sister, Sanskrit svasṛ

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Statistics for sister

Last Updated

12 Aug 2019

Look-up Popularity

Time Traveler for sister

The first known use of sister was before the 12th century

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More Definitions for sister



English Language Learners Definition of sister

: a girl or woman who has one or both of the same parents as you
informal used when talking to a woman
: a member of a religious community of women


sis·​ter | \ ˈsi-stər How to pronounce sister (audio) \

Kids Definition of sister

1 : a female person or animal related to another person or animal by having one or both parents in common
2 : a member of a religious society of women : nun
3 : a woman related to another by a common tie or interest

Other Words from sister

sisterly adjective


sis·​ter | \ ˈsis-tər How to pronounce sister (audio) \

Medical Definition of sister

chiefly British
: a head nurse in a hospital ward or clinic broadly : nurse

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More from Merriam-Webster on sister

Rhyming Dictionary: Words that rhyme with sister

Spanish Central: Translation of sister

Nglish: Translation of sister for Spanish Speakers

Britannica English: Translation of sister for Arabic Speakers

Comments on sister

What made you want to look up sister? Please tell us where you read or heard it (including the quote, if possible).


to move or obtain by small maneuvers

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