Definition of "nun"

nun¹

/nʌn/

noun
plural nuns
1. (Roman Catholicism, specifically) those living together in a cloister.
  Quotations
  Thus, when the nuns came to the mission and we saw that instead of murmuring soft blessings and gliding seraphically over the grass in diaphanous habits, they wore smart blouses and skirts and walked, laughed and talked in low twanging tones very much like our own American missionaries did, we were very disappointed.
  1988, Tsitsi Dangarembga, Nervous Conditions, Faber & Faber Limited (2021), page 258
2. (by extension) A member of a similar female community in other confessions.
3. (archaic, Britain, slang) A prostitute.
  Quotations
  Why laſt night, as Colonel Kill'em, Sir William Weezy, Lord Frederick Foretop, and I were careleſsly ſliding the Ranelagh round, picking our teeth, after a damn'd muzzy dinner at Boodle's, who ſhould trip by but an abbeſs, well known about town, with a ſmart little nun in her ſuite.
  1770, Samuel Foote, The Lame Lover, a Comedy in Three Acts. […], London: […] Paul Vaillant; and sold by P[eter] Elmsly […]; and Robinson and Roberts, […], Act I, page 12
  "I mean to inform you," answered the Oxonian, with a grin on his face, "that those three nymphs, who have so much dazzled your optics, are three nuns, and the plump female is Mother .... of great notoriety [...]"
  1881, Pierce Egan, chapter 8, in Life in London‎, page 205
4. A kind of pigeon with the feathers on its head like the hood of a nun.

nun²

/nʊn/

noun
plural nuns
1. The fourteenth letter of many Semitic alphabets/abjads (Phoenician, Aramaic, Hebrew, Syriac, Arabic and others).

nun³

pronoun
1. Pronunciation spelling of nothing.