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[sis-ter] /ˈsɪs tər/
a female offspring having both parents in common with another offspring; female sibling.
Also called half sister. a female offspring having only one parent in common with another offspring.
a female friend or protector regarded as a sister.
a thing regarded as feminine and associated as if by kinship with something else:
The ships are sisters.
a female fellow member, as of a church.
a female member of a religious community that observes the simple vows of poverty, chastity, and obedience.
British. a nurse in charge of a hospital ward; head nurse.
a fellow black woman.
a woman who supports, promotes, or participates in feminism.
Informal. a form of address used to a woman or girl, especially jocularly or contemptuously:
Listen, sister, you've had enough.
being or considered a sister; related by or as if by sisterhood:
sister ships.
having a close relationship with another because of shared interests, problems, or the like:
We correspond with school children in our sister city.
Biochemistry. being one of an identical pair.
Origin of sister
before 900; Middle English (noun) < Old Norse systir; cognate with Old English sweoster, Dutch zuster, German Schwester, Gothic swistar; akin to Serbo-Croatian sèstra, Lithuanian sesuõ, Latin soror (< *swesor), Old Irish siur, Welsh chwaer, Sanskrit svasar sister, Greek éor daughter, niece
Related forms
sisterless, adjective
sisterlike, adjective
nonsister, noun, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for sister
Contemporary Examples
Historical Examples
  • "But his sitting there eating in that—that shirt—" said his sister.

    The Spenders Harry Leon Wilson
  • "They needn't eat their lunch that way," declared his sister.

    The Spenders Harry Leon Wilson
  • It's the Viluca—Mr. Bines, you know; he's bringing his sister back to me.

    The Spenders Harry Leon Wilson
  • On his death-bed he charged his nephew to protect and cherish me as a sister.

    Philothea Lydia Maria Child
  • You wouldn't turn out your sister's son, would you, Uncle Paul?

    Brave and Bold Horatio Alger
British Dictionary definitions for sister


a female person having the same parents as another person
a female person who belongs to the same group, trade union, etc, as another or others
(informal) a form of address to a woman or girl, used esp by Black people in the US
a senior nurse
(mainly RC Church) a nun or a title given to a nun
a woman fellow member of a Church or religious body
(modifier) belonging to the same class, fleet, etc, as another or others: a sister ship
(modifier) (biology) denoting any of the cells or cell components formed by division of a parent cell or cell component: sister nuclei
Word Origin
Old English sweostor; related to Old Norse systir, Old High German swester, Gothic swistar
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
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Word Origin and History for sister

mid-13c., from Old English sweostor, swuster "sister," or a Scandinavian cognate (Old Norse systir, Swedish syster, Danish søster), in either case from Proto-Germanic *swestr- (cf. Old Saxon swestar, Old Frisian swester, Middle Dutch suster, Dutch zuster, Old High German swester, German Schwester, Gothic swistar).

These are from PIE *swesor, one of the most persistent and unchanging PIE root words, recognizable in almost every modern Indo-European language (e.g. Sanskrit svasar-, Avestan shanhar-, Latin soror, Old Church Slavonic, Russian sestra, Lithuanian sesuo, Old Irish siur, Welsh chwaer, Greek eor). French soeur "a sister" (11c., instead of *sereur) is directly from Latin soror, a rare case of a borrowing from the nominative case.

According to Klein's sources, probably from PIE roots *swe- "one's own" + *ser- "woman." For vowel evolution, see bury. Used of nuns in Old English; of a woman in general from 1906; of a black woman from 1926; and in the sense of "fellow feminist" from 1912. Meaning "female fellow-Christian" is from mid-15c. Sister act "variety act by two or more sisters" is from vaudeville (1908).

Online Etymology Dictionary, © 2010 Douglas Harper
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Slang definitions & phrases for sister



  1. Woman; girl • Used in direct address: Hey, sister, you'd better leave (1906+)
  2. A black woman (1926+ Black)
  3. A fellow feminist (1912+)

Related Terms

sob sister, weak sister

The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D.
Copyright (C) 2007 by HarperCollins Publishers.
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