soliloquy

Etymology

1595–1605; From Late Latin sōliloquium in the title of St. Augustine's Soliloquiorum libri duo ("Two Books of Soliloquies"), from sōlus (“only, sole”) + loquor (“I speak”).

noun

1. (drama) The act of a character speaking to themselves so as to reveal their thoughts to the audience.
   Coordinate term: aside
   At the end of the second act the main villain gave a soliloquy detailing his plans to attack the protagonist.
   Yet if I were to say […] that Hamlet's soliloquy had been much over-rated, it would not be said, on this account, that I was unable to appreciate Shakespeare. 1901, Edmund Selous, Bird Watching, J.M. Dent & Co, London, Chapter XII: Watching Blackbirds, Nightingales, Sand-martins, etc., page 315
2. (authorship) A speech or written discourse in this form.
   The feeling of Singleton's bosom grew heightened in its tone of melancholy, and a more passionate emphasis of thought broke forth in his half-muttered soliloquy:— ¶"How I remember as I look […] 1835, William Gilmore Simms, The Partisan, Harper, Chapter XI, page 135
   Here is a very over-simplified example, this time expressed in the form of a subjective soliloquy rather than a computer simulation. 1976, Richard Dawkins, The Selfish Gene, Kindle edition, OUP Oxford, published 2016, page 126

verb

1. (very rare) To issue a soliloquy.