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

Examples of sister in a Sentence

The sisters live in the convent.
Recent Examples on the Web Ingrid Tomás, Marvin’s sister, said finding a coyote isn't difficult. Karol Suarez, The Courier-Journal, "He fled Guatemala for a better life in the US. Instead, he found despair and death in Mexico," 27 Feb. 2021 Billy is soon joined in Isaiah’s house by a young woman whose sister was murdered by a serial killer. Washington Post, "Joe Ide’s IQ series continues with the idiosyncratic marvel ‘Smoke’," 26 Feb. 2021 The roster turned over just as often, complicated in part by a carousel of loan acquisitions from sister club Bologna of the Italian Serie A that showed varying levels of interest and effectiveness in MLS. Ian Nicholas Quillen, Forbes, "Thierry Henry’s Departure Feels Genuine, But Leaves CF Montreal In A Tough Spot," 26 Feb. 2021 Neither Blizzard Beach nor sister park Typhoon Lagoon returned to operation after Disney’s four-mouth shutdown last year. Dewayne Bevil,, "More water parks set to reopen, including Volcano Bay, Blizzard Beach," 26 Feb. 2021 Proust questionnaire and then reflects on her answers in this video from’s sister site, Vanity Fair. Cliff Pinckard, cleveland, "Gov. Mike DeWine outlines reopening for indoor entertainment venues: The Wake Up for Friday, Feb. 26, 2021," 26 Feb. 2021 An orchestra leader’s right-hand man befriends a little girl whose musician sister is pregnant. Los Angeles Times, "Movies on TV this week: ‘Gandhi’; ‘Forrest Gump’ and more," 26 Feb. 2021 Concordia wanted to sell the downtown Boise office building for $7.5 million to a sister institution, Concordia University St. Paul. oregonlive, "Concordia creditors do battle as campus slated for June foreclosure auction," 26 Feb. 2021 Among Bitwise’s consulting projects is for California, sister sites in other states, and for the nation. Carolyn Said, San Francisco Chronicle, "Oakland's Bitwise puts diverse students on path to tech success by paying them to learn," 25 Feb. 2021

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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Time Traveler for sister

Time Traveler

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

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Statistics for sister

Last Updated

1 Mar 2021

Cite this Entry

“Sister.” Dictionary, Merriam-Webster, Accessed 3 Mar. 2021.

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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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