# sister

> English word · Noun · IPA /ˈsɪs.tə(ɹ)/ · frequency rank #1,207

## Definitions
1. A daughter of the same parents as another person; a female sibling.
2. A female member of a religious order; especially one devoted to more active service; (informal) a nun.
3. Any butterfly in the genus Adelpha, so named for the resemblance of the dark-colored wings to the black habit traditionally worn by nuns.
4. A senior or supervisory nurse, often in a hospital.
5. Any woman or girl with whom a bond is felt through the same biological sex, gender or common membership in a community, race, profession, religion, organization, or ism.
6. A black woman.
7. A form of address to a woman.
8. A female fellow member of a religious community, church, trades union etc.
9. An entity that has a special or affectionate, non-hierarchical relationship with another.
10. A node in a data structure that shares its parent with another node.
11. Something in the same class.
12. One of two tornados that form in close proximity at the same time or in quick succession.

## Etymology
PIE word
 *swésōr
From Middle English sister, suster, from Old English swustor, sweoster, sweostor (“sister, nun”); from Proto-Germanic *swestēr (“sister”), from Proto-Indo-European *swésōr (“sister”).
Doublet of soror. Cognate with Scots sister, syster (“sister”), West Frisian sus, suster (“sister”), Dutch zuster (“sister”), German Schwester (“sister”), Norwegian Bokmål søster (“sister”), Norwegian Nynorsk and Swedish syster (“sister”), Icelandic systir (“sister”), Gothic 𐍃𐍅𐌹𐍃𐍄𐌰𐍂 (swistar, “sister”), Latin soror (“sister”), Russian сестра́ (sestrá, “sister”), Lithuanian sesuo (“sister”), Albanian vajzë (“girl, maiden”), Sanskrit स्वसृ (svásṛ, “sister”), Persian خواهر (xâhar, “sister”).
In standard English, the form with i is due to contamination with Old Norse systir (“sister”).
The plural sistren is from Middle English sistren, a variant plural of sister, suster (“sister”); compare brethren.
The sense for "Adelpha-genus butterfly" is a semantic loan from translingual Adelpha, itself from Ancient Greek ἀδελφή (adelphḗ, “sister”).

## Easily confused with
- **site** (https://plainspell.com/en/vs/sister-vs-site)
- **sites** (https://plainspell.com/en/vs/sister-vs-sites)
- **system** (https://plainspell.com/en/vs/sister-vs-system)
- **slater** (https://plainspell.com/en/vs/sister-vs-slater)
- **skater** (https://plainspell.com/en/vs/sister-vs-skater)
- **sitter** (https://plainspell.com/en/vs/sister-vs-sitter)
- **Sutter** (https://plainspell.com/en/vs/sister-vs-sutter)
- **Sumter** (https://plainspell.com/en/vs/sister-vs-sumter)
- **sisters** (https://plainspell.com/en/vs/sister-vs-sisters)
- **sitters** (https://plainspell.com/en/vs/sister-vs-sitters)
- **spinster** (https://plainspell.com/en/vs/sister-vs-spinster)
- **silver** (https://plainspell.com/en/vs/silver-vs-sister)
- **singer** (https://plainspell.com/en/vs/singer-vs-sister)
- **sinner** (https://plainspell.com/en/vs/sinner-vs-sister)
- **simmer** (https://plainspell.com/en/vs/simmer-vs-sister)
- **seater** (https://plainspell.com/en/vs/seater-vs-sister)
- **setter** (https://plainspell.com/en/vs/setter-vs-sister)
- **salter** (https://plainspell.com/en/vs/salter-vs-sister)
- **sicker** (https://plainspell.com/en/vs/sicker-vs-sister)
- **signer** (https://plainspell.com/en/vs/signer-vs-sister)

## Common misspellings (9)
`isster`, `sisetr`, `sisster`, `sisterr`, `sistre`, `sistter`, `sitser`, `ssister`, `ssiter`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/sister