From Middle English expounden, from Old French espondre, from Latin exponere. Doublet of expone and expose.

• IPA^(key): /ɪkˈspaʊnd/, /ɛkˈspaʊnd/

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• Rhymes: -aʊnd

expound (third-person singular simple present expounds, present participle expounding, simple past and past participle expounded)

1. (transitive) To set out the meaning of; to explain or discuss at length.

   Synonym: spell out

   Today I'll expound at length the theory propounded last week.

   • 1891, Oscar Wilde, chapter III, in The Picture of Dorian Gray, London; New York, N.Y.: Ward Lock & Co., →OCLC, pages 63–64:

     “[…] Some day, when you are tired of London, come down to Treadley, and expound to me your philosophy of pleasure over some admirable Burgundy I am fortunate enough to possess.”

   • 1891, John Stuart Verschoyle, The History of Modern Civilization: A Handbook, page 204:

     Ramus, fascinated by Plato and by the dialogues in which Socrates expounds his ideas with as much simplicity as freedom, endeavoured to Socratise in his turn.

   • 2016, Enric Pérez, Blai Pié i Valls, “Bohr and Ehrenfest: transformations and correspondences in the early 1920s”, in European Physical Journal H, volume 41, →DOI, page 108:

     The impossibility of explaining the Stern-Gerlach result is what he and Ehrenfest tried to show with their “little calculation”. This joint paper had a markedly Ehrenfestian character, as in it, after expounding several arguments, the issue remains open.

2. (intransitive, with on or upon) To make a statement, especially at length.

   He expounded often on the dangers of the imperial presidency.

   • 2021 December 29, Stephen Roberts, “Stories and facts behind railway plaques: Evesham (1870)”, in RAIL, number 947, page 59:

     Fowler was also interested in metallurgy and the use of new materials that could withstand greater stresses, something he expounded on when giving his presidential address to the new Institution of Mechanical Engineers in 1927.