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

There’s another complication: Last year, I gave my sister $25,000 from our joint savings when her divorce was about to cost her the house.

From MarketWatch ● Nov. 6, 2026

Gardner writes the bulk of the bathroom guides, covering between 120 and 150 films a year, with help from his sister and a handful of contributors.

From The Wall Street Journal ● Nov. 6, 2026

"We thought that maybe there was a mistake, so I didn't tell my sister."

From BBC ● Nov. 3, 2026

Wright is survived by his husband, father, sister and niece.

From Los Angeles Times ● Nov. 3, 2026

One as good as the next, so long as she wasn’t known to his sister, his family.

From "The Red Car to Hollywood" by Jennie Liu

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

From Slate ● Nov. 6, 2026

“Nicole, the oldest of us three sisters, will be greatly missed,” Nika and Natalie posted on their official site.

From Los Angeles Times ● Nov. 3, 2026

In a tribute on the country music-focused website, her colleague Evan Paul related the story of first meeting Nicole and her sisters and his later interactions with her at the media outlet.

From Los Angeles Times ● Nov. 3, 2026

But Rick Macci, the veteran American coach who guided the Williams sisters as teenagers, believes Ferrero will find it harder to improve Shelton's technical deficiencies.

From BBC ● Nov. 2, 2026

But there was no need for worry; the famous Fox sisters were given special treatment.

From "American Spirits" by Barb Rosenstock

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Related Words

• relative
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