• synonyms


[ob-vur-zhuh n, -shuh n]
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  1. an act or instance of obverting.
  2. something that is obverted.
  3. Logic. a form of inference in which a negative proposition is obtained from an affirmative, or vice versa, as “None of us is immortal” is obtained by obversion from “All of us are mortal.”

Origin of obversion

1840–50; < Late Latin obversiōn- (stem of obversiō) a turning toward, equivalent to obvers(us) (see obverse) + -iōn- -ion
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for obversion

Historical Examples

  • A further process, known as Contraposition or Conversion by Negation, consists of conversion following on obversion.

    Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3


  • In this it differs from Obversion, Conversion, and Contraposition, each of which stands for one process.


    Carveth Read