See also: Sister



PIE word

From Middle English sister, suster, from Old English swustor, sweoster, sweostor (sister, nun); from Proto-Germanic *swestēr (sister), from Proto-Indo-European *swésōr (sister).

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.



sister (plural sisters or (archaic in most senses) sistren)

  1. A daughter of the same parents as another person; a female sibling.
    Synonym: (slang) sis
    Antonym: brother
    Hypernym: sibling
    My sister is always driving me crazy.
  2. A female member of a religious order; especially one devoted to more active service; (informal) a nun.
    Synonym: nun
    Coordinate terms: brother, friar, frater
    Michelle left behind her bank job and became a sister at the local convent.
  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. (Britain) A senior or supervisory nurse, often in a hospital.
    Synonym: charge nurse
  5. Any woman or girl with whom a bond is felt through common membership in a community, race, profession, religion, organization, or ism.
    Connie was very close to her friend Judy and considered her to be her sister.
    • 1985, “Sisters Are Doin’ It for Themselves”, in Who’s Zoomin' Who?, performed by Eurythmics and Aretha Franklin:
      Sisters are doing it for themselves / Standing on their own two feet
  6. (slang, sometimes capitalized) A black woman.
    • 2009, Rajen Persaud, Why Black Men Love White Women, Simon and Schuster, →ISBN, page 171:
      The short “naps” of the average Sister do not sway in the wind as that of a blonde.
  7. (informal) A form of address to a woman.
    Synonyms: darling, dear, love, (US) lady, miss, (northern UK) pet
    What’s up, sister?
  8. A woman, in certain religious, labour or socialist circles; also as a form of address.
    Thank you, sister. I would like to thank the sister who just spoke.
  9. (attributively) An entity that has a special or affectionate, non-hierarchical relationship with another.
    Synonyms: affiliate, affiliated
    sister publication
    sister city
    sister projects
  10. (computing theory) A node in a data structure that shares its parent with another node.
  11. (usually attributively) Something in the same class.
    sister ships
    sister facility

Usage notesEdit

  • In Roman Catholicism, a distinction is often drawn (especially by members of female religious orders) between nuns and sisters, the former being cloistered and devoted primarily to prayer, the latter being more active, doing work such as operating hospitals, caring for the poor, or teaching.
  • The plural sistren is no longer commonly used for biological sisters in contemporary English (although it was in the past) but may be found in some religious, feminist, or poetic usage.

Coordinate termsEdit

Derived termsEdit

Related termsEdit


  • Gulf Arabic: سِسْتَر(sistar, female nurse)
  • Japanese: シスター (shisutā)
  • Korean: 시스터 (siseuteo)



sister (third-person singular simple present sisters, present participle sistering, simple past and past participle sistered)

  1. (transitive, construction) To strengthen (a supporting beam) by fastening a second beam alongside it.
    I’m trying to correct my sagging floor by sistering the joists.
  2. (obsolete, transitive) To be sister to; to resemble closely.


Further readingEdit


Middle EnglishEdit



  1. Alternative form of suster



From Middle English sister, syster, forms of suster influenced by Old Norse systir, from Old English sweostor, swustor, sweoster, from Proto-Germanic *swestēr, from Proto-Indo-European *swésōr.



sister (plural sisteris)

  1. sister

Derived termsEdit