sister
Americannoun
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sisters
plural
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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:
Your close relationship with your sister will be a big advantage when sorting through your mother’s estate.
From MarketWatch ● Sep. 27, 2026
I have one sister and we are on good terms regarding how everything should be divided.
From MarketWatch ● Sep. 27, 2026
Walton competed at a high level in gymnastics after following his sister into the sport, but boxing remained his obsession.
From BBC ● Sep. 26, 2026
Morgan wasn’t working at the Mirror or its sister Sunday paper at the time.
From The Wall Street Journal ● Sep. 24, 2026
I was just a girl with her little sister, strolling through the city together.
From "Code Name Kingfisher" by Liz Kessler
As Barb watched more of her sisters repeat the same hair-raising behaviors, she grew too scared to learn the results of her own genetic test.
From The Wall Street Journal ● Sep. 25, 2026
The idea for the group came from playing the video game “Rock Band,” which led the sisters to performing at local “Battle of the Bands” competitions and posting cover songs to YouTube.
From Los Angeles Times ● Sep. 24, 2026
Four siblings — two brothers and two sisters — had grown up in that home.
From MarketWatch ● Sep. 24, 2026
The three sisters, here as teenagers with their father, died in the sea.
From BBC ● Sep. 20, 2026
The ladylike Fox sisters did not seem like swindlers.
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.
