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

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

See Examples For:

sister sisters

I wanted to surprise my sister with concert tickets so I went out and bought them for the two of us, but it turns out she can’t make it on the day I picked.

From MarketWatch ● Oct. 3, 2026

Her sister, Duch, was celebrating just as enthusiastically — but without the alcohol.

From Los Angeles Times ● Oct. 3, 2026

Kim Yo Jong, the powerful sister of North Korea's leader, responded by calling Seoul "really despicable" on Friday and once again denied Pyongyang was behind the blasts.

From Barron's ● Oct. 3, 2026

Pelkey's sister, Stacey Wales, told the BBC last year the family had used voice recordings, videos and pictures to recreate him for the AI video.

From BBC ● Oct. 2, 2026

I felt a bit like a criminal, spying on my sister.

From "Code Name Kingfisher" by Liz Kessler

"There are no words that can truly describe the heartbreak and devastation his parents, sisters and our whole family are experiencing," Jones said on the fund-raiser page.

From BBC ● Oct. 3, 2026

By October 2022, rumors were flying that the sisters were fighting over their mother’s will, a claim that Wynonna shot down while speaking with People.

From Los Angeles Times ● Oct. 1, 2026

English cricketers aiming to play in a men's T20 franchise tournament organised by the Afghanistan Cricket Board have been urged to think about their "daughters, sisters or mothers".

From BBC ● Sep. 30, 2026

The family wrote, “She was adored by her sisters and she was deeply loved by her parents. In fact, she was the light of our lives.”

From Los Angeles Times ● Sep. 30, 2026

Part of the audience took the idea of talking to the dead seriously, others must have come to whisper about the reputations of the two Fox sisters.

From "American Spirits" by Barb Rosenstock

Related Words

• relative
• twin