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:
"It would absolutely break my heart to have to sell but it's something that we have to consider," she said, explaining she and her sister now face an estimated £7,000 yearly council tax bill.
From BBC ● Jul. 28, 2026
In early 1999, Lieberson put her career on hold to nurse her sister Alexis, who was gravely ill from breast cancer.
From The Wall Street Journal ● Jul. 28, 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
I looked at my sister kneeling beside me in the light of burning Holland.
From "The Hiding Place" by Corrie ten Boom
The victims of the crash were Alpha Phi sorority sisters Niamh Rolston, 20; Peyton Stewart, 21; Asha Weir, 21; and Deslyn Williams, 21, who all received their degrees posthumously.
From Los Angeles Times ● Jul. 28, 2026
And then we went home and I called my sisters and asked them questions.
From Los Angeles Times ● Jul. 26, 2026
Cathy Stoyko said she was "dancing for her sisters" back home in Vancouver Island, Canada.
From BBC ● Jul. 26, 2026
She rents it out, and while she’s never discussed her estate plans with me, I’ve assumed she might leave the house to me and my two sisters.
From MarketWatch ● Jul. 23, 2026
Just as it was getting dark, the Fox sisters settled themselves at the parlor table among the other guests, joined hands, prayed, and waited for the spirits.
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.
