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

After moving with her family to Florence, Edda followed a sister to the United States. Emily Langer, Washington Post, "Edda Servi Machlin, Holocaust survivor who kept alive Italian Jewish cuisine, dies at 93," 6 Sep. 2019 But there are other truths as well and Hong Kong and Shanghai — its sister city in history and spirit — embody them. Jonathan Kaufman,, "Are Hong Kong protests a preview of China’s uncertain future?," 6 Sep. 2019 In the Bay Area, the San Francisco Rapid Response Network, along with sister networks across California, serves as the front line of the local fight against the current wave federal immigration mandates. NBC News, "Yearning to Breathe Free: Meet the Press Film Festival with AFI," 6 Sep. 2019 Zillow economists looked at rental data from nine metro areas drawn from its online listings and its sister-site, HotPads. Louis Hansen, The Mercury News, "California rent cap measure could have limited impact," 5 Sep. 2019 The discovery sheds light on the most relatable trait yet of mysterious ancient humans known as Denisovans, a sister group to Neanderthals, that was discovered in 2010. Ashley Strickland, CNN, "Neanderthal-like human relatives had hands similar to modern humans, study says," 5 Sep. 2019 Aitheras and a sister company, AcuteAir Ambulance of Fort Lauderdale, have set up a gofundme account for tax-deductible donations to the Icarus Foundation to support company efforts in the Bahamas. Grant Segall,, "Cleveland’s Aitheras Aviation rescuing Hurricane Dorian victims in the Bahamas," 5 Sep. 2019 According to an annual index compiled by the Economist Intelligence Unit (EIU), a sister company of The Economist, the Austrian capital is the most liveable city in the world for the second year running. The Economist, "Vienna remains the world’s most liveable city," 4 Sep. 2019 Domenic Selga told CBS News his mother, step-father and three step-sisters were among the victims. CBS News, "33 bodies recovered after California boat fire, 1 missing," 4 Sep. 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

9 Sep 2019

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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

Thesaurus: All synonyms and antonyms for sister

Spanish Central: Translation of sister

Nglish: Translation of sister for Spanish Speakers

Britannica English: Translation of sister for Arabic Speakers

Comments on sister

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authorized for issue (as a bond)

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