sister
Americannoun
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a female offspring having both parents in common with another offspring; female sibling.
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Also called half sister. a female offspring having only one parent in common with another offspring.
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a female friend or protector regarded as a sister.
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a thing regarded as feminine and associated as if by kinship with something else.
The ships are sisters.
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a female fellow member, as of a church.
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a female member of a religious community that observes the simple vows of poverty, chastity, and obedience.
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British. a nurse in charge of a hospital ward; head nurse.
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Informal. a term used to refer to or address a fellow Black woman; soul sister.
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a woman who supports, promotes, or participates in feminism.
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Informal. a form of address used to a woman or girl, especially jocularly or contemptuously.
Listen, sister, you've had enough.
adjective
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being or considered a sister; related by or as if by sisterhood.
sister ships.
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having a close relationship with another because of shared interests, problems, or the like.
We correspond with school children in our sister city.
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Biochemistry. being one of an identical pair.
noun
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a female person having the same parents as another person
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a female person who belongs to the same group, trade union, etc, as another or others
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informal a form of address to a woman or girl, used esp by Black people in the US
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a senior nurse
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RC Church a nun or a title given to a nun
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a woman fellow member of a Church or religious body
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(modifier) belonging to the same class, fleet, etc, as another or others
a sister ship
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(modifier) biology denoting any of the cells or cell components formed by division of a parent cell or cell component
sister nuclei
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of sister
First recorded before 900; Middle English (noun) from Old Norse systir; cognate with Old English sweoster, Dutch zuster, German Schwester, Gothic swistar; akin to Serbo-Croatian sèstra, Lithuanian sesuõ, Latin soror (from unattested swesor ), Old Irish siur, Welsh chwaer, Sanskrit svasar “sister,” Greek éor “daughter, niece”
Explanation
Your sister is your female sibling. If your parents have six children, and all of them are girls, that means you have five sisters. Your biological sister has the same mother and father that you have, but some sisters are adopted, or even have a different mom or dad (some people call this a stepsister or a half-sister). If you join a college sorority or a trade union, you'll refer to the other members as your sisters. Catholic nuns and other religious women are also called sisters. The roots of sister go back to words meaning "one's own" and "woman."
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:
Araspe, the king of Cyprus, and his sister, Elisa, are in love with these two exiles and determined to have them no matter what.
From The Wall Street Journal ● Jul. 28, 2026
Abigail secured third place in the women's vault, one place ahead of sister Emily, who then claimed her own medal later in the afternoon by finishing third in the uneven bars.
From BBC ● Jul. 27, 2026
The layoffs, outlined in a Securities and Exchange Commission filing on Monday, will affect about 180 staff and contract positions across BuzzFeed and its sister brands HuffPost and Tasty.
From Los Angeles Times ● Jul. 27, 2026
Simon began singing with her sister in the 1960s.
From Barron's ● Jul. 27, 2026
The whole thing about the dead sister, the questions from the Friday before — all of it seemed pointless now.
From "Firegirl" by Tony Abbott
The Díaz sisters spoke to The Times about their season of upheaval and the recovery that informed their first independent outing yet.
From Los Angeles Times ● Jul. 28, 2026
One of my sisters is 75 and disabled, and the other is 80 and lives across the country.
From MarketWatch ● Jul. 23, 2026
In 2008, one sister triplet was miscarried, while two of her sisters lived "for a significant amount of time", but NUH registered all three babies as miscarriages.
From BBC ● Jul. 18, 2026
Living with Laron syndrome can be challenging, the sisters say.
From BBC ● Jul. 17, 2026
Most participants didn’t detail the sister’s actions; and, unlike the dead, the sisters weren’t talking.
From "American Spirits" by Barb Rosenstock
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
