sister

Pluralsisters

Formssisters, sistering, sistered

1. 1
   female siblingnouncountable

   A female sibling: a girl or woman who shares one or both parents with another person.

   Her sister flew in from Chicago for the wedding.

   The two sisters ran the family bakery together.

   UsageSay older or younger sister, or informally big and little sister. The short form is sis.

   Similarsis

   Oppositebrother

   Note

   The family sense the rest of the word grows from, and one of the oldest words in English: Old English sweostor, from a Proto-Indo-European root that also gave Latin soror, so sister and soror are cognates. The old plural sistren dropped out of plain use long ago but lingers in jocular "brethren and sistren" and in some religious, feminist, and Rastafarian speech. Source

   Checked 3 Nov 2026 · 4 facts

   • The family meaning is inherited from Old English. en.wiktionary.org
   • Sister belongs to English's ancient inherited vocabulary, descending from Old English sweostor and ultimately Proto-Indo-European. en.wiktionary.org
   • Latin soror descends from the same Proto-Indo-European ancestor, making it cognate with sister. en.wiktionary.org
   • Sistren is an old plural of sister that ceased to be ordinary, unmarked usage. en.wiktionary.org
2. 2
   equal partnernounbefore a noun

   Something closely related to another of the same kind, as an equal partner or near match, as in sister city or sister ship.

   The festival was planned with help from our sister city in northern Italy.

   Our sister company in Ohio handles all the shipping.

   Similartwin, partner, sibling

   Note

   What it adds is closeness and equal standing: two partners side by side rather than ranked, whether linked by choice or by common ownership. Affiliate is its drier synonym. It also stretches to members of one class, such as sister ships built to a shared design, which need not be partners at all. Source

   Checked 3 Nov 2026 · 1 fact

   • Sister ships can be members of the same ship class or share essentially the same design, without partnership being a defining requirement. en.wikipedia.org
3. 3
   kindred womannouncountable

   A woman or girl regarded as sharing a bond with others through gender, race, or membership in a community, profession, faith, or movement.

   Every woman who has fought for equal pay is my sister in this struggle.

   The activists addressed one another as sisters throughout the campaign.

   Note

   Solidarity is the point here: the bond comes from shared identity or cause rather than from family. The 1985 song "Sisters Are Doin' It for Themselves" uses the plural as a rallying cry for independent women. In this use the word is warm and inclusive, and it can embrace a friend, a colleague or a whole movement. In informal African American English it is also simply a word for a Black woman, as brother is for a Black man. Source

   Checked 3 Nov 2026 · 2 facts

   • “Sisters Are Doin' It for Themselves” is a 1985 song. eurythmics.com
   • The song serves as an anthem for women's independence. annielennox.com
4. 4
   nunnouncountable

   A woman who is a member of a religious order, especially one devoted to active service; informally, a nun.

   A sister from the local order ran the soup kitchen.

   The sisters cared for orphans throughout the region.

   UsageAs a title before a name, it takes a capital: Sister Agnes.

   Similarnun

   Oppositebrother

   Note

   The religious sense extends the family word to women who share a common life under vows, and Sister is also their usual title, as in Sister Mary. In careful use, a sister belongs to an order given to active service in the world, while a nun, strictly, lives in an enclosed, contemplative order. Source

   Checked 3 Nov 2026 · 3 facts

   • Women in religious communities share a religious life under vows. dioceseofraleigh.org
   • Sister is used as a title before a woman's religious name. catholicarchives.bc.edu
   • The conventional religious distinction associates sisters with active service and nuns with enclosed, contemplative life. vocationnetwork.org

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