sister

plural sisters · archaic plural sistren

1. A daughter of the same parents as another person; a female sibling.

   My sister is always driving me crazy.

   Synonyms: sis · Antonyms: brother

2. A female member of a religious order; especially one devoted to more active service; (informal) a nun.

   Michelle left behind her bank job and became a sister at the local convent.

   Synonyms: 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. UKA senior or supervisory nurse, often in a hospital.

   Synonyms: charge nurse

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.

   Connie was very close to her friend Judy and considered her to be her sister.

   2 more examples

   Sisters are doing it for themselves / Standing on their own two feet

   1985, “Sisters Are Doin’ It for Themselves”, in Who’s Zoomin' Who?, performed by Eurythmics and Aretha Franklin

   In standing up for our Muslim brothers and sisters in detention centers, we stand up for ourselves, and our own liberties.

   2020 August 20, Eliezer Brand, “ICE is forcing Muslims to eat pork. My fellow Orthodox Jews: This is our fight!”, in The Forward, archived from the original on 24 Oct 2020

6. capitalizedslangsometimesAfrican-American VernacularA black woman.

   The short “naps” of the average Sister do not sway in the wind as that of a blonde.

   2009, Rajen Persaud, Why Black Men Love White Women, Simon and Schuster, →ISBN, page 171

   2 more examples

   A fly sister rolled in with a suitcase full of hip-hop novels called The Glamorous Life, and an African brother with long dreads wanted to sell them some incense and some fake Jacob watches.

   2006, Noire [pseudonym], Thug-A-Licious: An Urban Erotic Tale, New York, N.Y.: One World, Ballantine Books, →ISBN, page 169

   And now, social media has made it worse. From Facebook to Twitter, I get all kinds of invitations. Recently a sister inboxed me on Facebook and told me that she knew for a fact that I wanted her and she wanted me.

   2014, J. L. King, Full Circle: Loving. Living. Life. After The Down Low

7. informalA form of address to a woman.

   What’s up, sister?

   1 more example

   "Listen, sister. I've got a job for you."

   1932, Delos W. Lovelace, King Kong, published 1965, page 13

   Synonyms: darling, dear, love, lady, miss, pet

8. A female fellow member of a religious community, church, trades union etc.

   Thank you, sister. I would like to thank the sister who just spoke.

9. attributiveAn entity that has a special or affectionate, non-hierarchical relationship with another.

   sister city

   3 more examples

   sister publication

   sister projects

   The RMS Olympic and its sister ship, the Titanic, were nearly identical in every way — but the Olympic survived its two brushes with disaster and remained in service until it was sold for scrap metal in 1935.

   2026 September 8, William DeLong, Cara Johnson, “How The RMS Olympic Narrowly Averted The Tragic Fate Of The Titanic”, in All That's Interesting, archived from the original on 08 Sep 2026

   Synonyms: affiliate, affiliated

10. computingA node in a data structure that shares its parent with another node.
11. attributiveusuallySomething in the same class.

    sister ships

    4 more examples

    sister facility

    Within the ABCZ clade, Arecanae are sister of a group that includes all of the other taxa, and the latter fall into two major clades.

    2000, Dennis W. Stevenson, Jerrold I. Davis, John V. Freudenstein, Christopher R. Hardy, Mark P. Simmons, Chelsea D. Specht, “A phylogenetic analysis of the monocotyledons based on morphological and molecular character sets, with comments on the placement of Acorus and Hydatellaceae”, in Karen L[ouise] Wilson, David A. Morrison, editors, Monocots: Systematics and Evolution, Collingwood, Vic.: CSIRO Publishing, →ISBN, page 21, column 1

    Karimi (1999) and Cheng et al. (1997), among others, on the other hand, assume that specific objects are base-generated at SpecVP, whereas nonspecific objects are sister of V.

    2006, Linguistics, number 401, page 11

    The bee-eaters are sister to a clade that includes the rollers, ground-rollers, todies, motmots, and kingfishers (Cracraft 2013).

    2016, Bruce M. Beehler, Thane K. Pratt, Birds of New Guinea: Distribution, Taxonomy, and Systematics, Princeton, N.J.; Woodstock, Oxon: Princeton University Press, →ISBN, page 220

12. One of two tornados that form in close proximity at the same time or in quick succession.

present singular third person sisters · participle present sistering · participle past sistered · past sistered

1. transitivebusinessTo strengthen (a supporting beam) by fastening a second beam alongside it.

   I’m trying to correct my sagging floor by sistering the joists.

2. obsoletetransitiveTo be sister to; to resemble closely.

   Deep clerks she dumbs; and with her needle composes Nature's own shape, of bud, bird, branch, or berry, That even her art sisters the natural roses; Her inkle, silk, twin with the rubied cherry

   c. 1607–1608 (date written), William Shakespeare, [George Wilkins?], The Late, and Much Admired Play, Called Pericles, Prince of Tyre. […], London: […] [William White and Thomas Creede] for Henry Gosson, […], published 1609, →OCLC, [Act V, scene i]

plural Sisters

1. Title of respect for an adult female member of a religious order.

   Could you say a prayer for me, Sister?

   2 more examples

   At the convent, Sister Grace supervises the kitchen.

   Please welcome Sister Smith as she moves from her former congregation to her new congregation.

2. Title of respect for an adult female member of a fraternal/sororal organization, or comrade in a movement, or even a stranger using fictive kin.

   Sister Huerta was to have been our initial speaker this morning. However, we received word later this morning that Sister Huerta would be unable to attend our convention.

   1983, Official Proceedings, Resolutions, Constitution and Merger Agreement of the United Food and Commercial Workers International Union Convention

   Synonyms: Sis., Sr., Ss.

3. A title used to personify or respectfully refer to concepts or animals.

   Native American leader Chief Seattle urged ecological responsibility, referring to Brother Eagle and Sister Sky in his purported 1854 speech.