[dis-juhngk-shuh n]


the act of disjoining or the state of being disjoined: a disjunction between thought and action.
  1. Also called disjunctive, inclusive disjunction.a compound proposition that is true if and only if at least one of a number of alternatives is true.
  2. Also called exclusive disjunction.a compound proposition that is true if and only if one and only one of a number of alternatives is true.
  3. the relation among the components of such a proposition, usually expressed by AND or V.

Origin of disjunction

1350–1400; Middle English disjunccioun < Latin disjunctiōn- (stem of disjunctiō) separation, equivalent to disjunct(us) (see disjunct) + -iōn- -ion
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for disjunction

Contemporary Examples of disjunction

Historical Examples of disjunction

  • Disjunction is more frequent in dry fruits than in fleshy ones.

    Vegetable Teratology

    Maxwell T. Masters

  • Thus the disjunction "universal-particular" includes all objects.

  • What bodes this rare conjunction and disjunction of man and wife and of old affections?

    Old Friends

    Andrew Lang

  • Is not that disjunction the ultimate word of Logic in the matter, and can any disjunction, as such, resolve itself?

  • A question might be defined as a disjunctive judgment in which one member of the disjunction is expressed and the others implied.

British Dictionary definitions for disjunction



Also called: disjuncture the act of disconnecting or the state of being disconnected; separation
cytology the separation of the chromosomes of each homologous pair during the anaphase of meiosis
  1. the operator that forms a compound sentence from two given sentences and corresponds to the English or
  2. a sentence so formed. Usually written pq where p, q are the component sentences, it is true (inclusive sense) whenever either or both of the latter are true; the exclusive disjunction, for which there is no symbol, is true when either but not both disjuncts is
  3. the relation between such sentences
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for disjunction

c.1400, disjunccioun, from Old French disjunction (13c.) or directly from Latin disjunctionem "separation," noun of action from past participle stem of disjungere (see disjointed).

Online Etymology Dictionary, © 2010 Douglas Harper

disjunction in Medicine




The separation of homologous chromosomes during meiosis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.