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

Tucked out of sight is a photo of her sister Beatrice Khalayi, 58, who died when intense rains caused widespread destruction in Kibera.

From BBC ● Nov. 11, 2026

First we visit Lakeside Memorial Cemetery in Holly, Mich., where my parents, my sister and generations of my family are interred.

From The Wall Street Journal ● Nov. 9, 2026

Anthropic president Daniela Amodei, Dario's sister, is married to Holden Karnofsky, an Anthropic employee and a leading EA proponent.

From Barron's ● Nov. 9, 2026

So I mean, my sister, you know, she doesn’t go back down that path every day.

From Slate ● Nov. 8, 2026

There are children depending on me, and their lives are more important than a silly argument with my sister.

From "Code Name Kingfisher" by Liz Kessler

The question swam into my mind—a principal character sports one—during the musical “Wanted,” about a pair of black sisters who go on a righteous crime spree in the state in 1893.

From The Wall Street Journal ● Nov. 11, 2026

"They're still waiting," she said, referring to the wives, mothers, daughters and sisters not yet reunited with their captured loved ones.

From Barron's ● Nov. 9, 2026

The fifth and final day, known as Bhai Dooj, celebrates the bond between brothers and sisters.

From BBC ● Nov. 6, 2026

Maines and her bandmates, sisters Martie Maguire and Emily Strayer, required beefed-up personal security.

From Slate ● Nov. 6, 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

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Related Words

• relative
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