sister

American  

[sis-ter] / ˈsɪs tər /

noun

• sisters
  plural

1. a female offspring having both parents in common with another offspring; female sibling.

2. Also called half sister. a female offspring having only one parent in common with another offspring.

3. stepsister.

4. a female friend or protector regarded as a sister.

5. a thing regarded as feminine and associated as if by kinship with something else.

   The ships are sisters.

6. a female fellow member, as of a church.

7. a female member of a religious community that observes the simple vows of poverty, chastity, and obedience.

8. British. a nurse in charge of a hospital ward; head nurse.

9. Informal. a term used to refer to or address a fellow Black woman; soul sister.

10. a woman who supports, promotes, or participates in feminism.

11. Informal. a form of address used to a woman or girl, especially jocularly or contemptuously.

    Listen, sister, you've had enough.

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adjective

1. being or considered a sister; related by or as if by sisterhood.

   sister ships.

2. having a close relationship with another because of shared interests, problems, or the like.

   We correspond with school children in our sister city.

3. Biochemistry. being one of an identical pair.

sister British  

/ ˈsɪstə /

noun

1. a female person having the same parents as another person

2. See half-sister stepsister

3. a female person who belongs to the same group, trade union, etc, as another or others

4. informal a form of address to a woman or girl, used esp by Black people in the US

5. a senior nurse

6. RC Church a nun or a title given to a nun

7. a woman fellow member of a Church or religious body

8. (modifier) belonging to the same class, fleet, etc, as another or others

   a sister ship

9. (modifier) biology denoting any of the cells or cell components formed by division of a parent cell or cell component

   sister nuclei

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Other Word Forms

Derived Forms

• nonsister
  noun
• sisterless
  adjective
• sisterlike
  adjective

Inflected Forms

Nouns

• sisters
  plural

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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”

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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

See Examples For:

sister sisters

"How to tell you something without picking up my phone to call you. How to be your sister in a world that I can't reach for you in," she wrote.

From BBC ● Oct. 18, 2026

In female mice, two "sister" cells produced by the division of a single parent cell frequently make the same developmental decision at the same time.

From Science Daily ● Oct. 18, 2026

Her uncle Stanislaw Radziwill married Jackie Kennedy’s sister “Lee” Bouvier, and d’Ornano still lives by a lesson Jackie taught her shortly before her death.

From The Wall Street Journal ● Oct. 18, 2026

For example, how he treats his little sister, how they handle conflict at home, and whether Everett apologizes when he gets something wrong.

From Salon ● Oct. 18, 2026

His eyes shift, and I follow his gaze to my left, where it lands on his mom, his grandma, and his little sister, Quinn, who’s probably eight or nine now.

From "Keeping Pace" by Laurie Morrison

Trisha Addicks, who runs a sorority recruitment consulting firm and regularly speaks with sisters at campuses nationwide, recalls a “wild west” when she was in college in the late 1980s.

From The Wall Street Journal ● Oct. 18, 2026

Williams lives with her sisters in the bottom unit of her three-family townhouse.

From The Wall Street Journal ● Oct. 17, 2026

But once again, the sisters put in the work to improve and became key pieces for their team.

From Los Angeles Times ● Oct. 16, 2026

Horton was known as the more outgoing and gregarious of the pair, but both sisters were described as being inquisitive, opinionated, fiercely loyal and competitive.

From Los Angeles Times ● Oct. 16, 2026

Leah told supporters that she and her sisters would never follow such scandalous directions, no matter what their spirit friends wished.

From "American Spirits" by Barb Rosenstock

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Related Words

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