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:
Searches for “Dario Amodei’s wife” on Google often turn up a photograph of his sister, Daniela Amodei, who helps run the company.
From The Wall Street Journal ● Aug. 14, 2026
Brophy’s brother Ramon Fabregas was a part of volunteer efforts to search the state park for his sister last month.
From Los Angeles Times ● Aug. 14, 2026
She was a mother, a sister, a daughter, a friend and a beloved family member.
From BBC ● Aug. 12, 2026
Her mother, 72-year-old Luz Marina, recently suffered a thrombosis, and her sister Sandra, 38, ended up in a wheelchair because of meningitis.
From Barron's ● Aug. 11, 2026
I felt a bit like a criminal, spying on my sister.
From "Code Name Kingfisher" by Liz Kessler
The sisters both said they would typically be praying quietly in their rooms early on a Sunday, ahead of attending Mass.
From Salon ● Aug. 12, 2026
Catholic sisters are playing a key role among clergy and other religious leaders who have been organizing demonstrations and vigils at ICE field offices and processing centers in places like Chicago, Pittsburgh and Philadelphia.
From Salon ● Aug. 12, 2026
"I feel like we're like sisters," says Hunter Bell.
From BBC ● Aug. 10, 2026
The Williams sisters have won 14 Grand Slam doubles titles and three Olympic gold medals together.
From Los Angeles Times ● Aug. 5, 2026
Later, when Ruth visited the Fox sisters in Rochester, she began to “suspect that they were deceiving.”
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.
