[ dih-soh-see-ey-shuhn, -shee-ey- ]
See synonyms for dissociation on Thesaurus.com
  1. an act or instance of dissociating.

  2. the state of being dissociated; disjunction; separation: the dissociation of church and state.

  1. Physical Chemistry.

    • the reversible resolution or decomposition of a complex substance into simpler constituents caused by variation in physical conditions, as when water gradually decomposes into hydrogen and oxygen under great heat in such a way that when the temperature is lowered the liberated elements recombine.

  2. Psychiatry. the splitting off of a group of mental processes from the main body of consciousness, as in amnesia or certain forms of hysteria.

Origin of dissociation

First recorded in 1605–15; dis-1 + (as)sociation, modeled on Latin dissociātiō “separation”

Other words from dissociation

  • self-dis·so·ci·a·tion, noun

Words Nearby dissociation

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use dissociation in a sentence

  • There seems to be very little known about dissociation, and somewhat vague theories have been advanced to explain the phenomenon.

    Aviation Engines | Victor Wilfred Pag
  • In certain conditions they are capable of dissociation, and they last for a longer or a shorter time.

    Reincarnation | Th. Pascal
  • Psychologists will explain his experience by the word “dissociation.”

    Alfred Tennyson | Andrew Lang
  • Within ten minutes their dissociation was final and absolute.

    Joan Thursday | Louis Joseph Vance
  • The theory of dissociation has, as far as I know, no opponents.

British Dictionary definitions for dissociation


/ (dɪˌsəʊsɪˈeɪʃən, -ʃɪ-) /

  1. the act of dissociating or the state of being dissociated

  2. chem

    • a reversible chemical change of the molecules of a single compound into two or more other molecules, atoms, ions, or radicals

    • any decomposition of the molecules of a single compound into two or more other compounds, atoms, ions, or radicals

  1. separation of molecules or atoms that occurs when a liquid or solid changes to a gas

  2. psychiatry the separation of a group of mental processes or ideas from the rest of the personality, so that they lead an independent existence, as in cases of multiple personality

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

Scientific definitions for dissociation


[ dĭ-sō′sē-āshən ]

  1. The separation of a substance into two or more simpler substances, or of a molecule into atoms or ions, by the action of heat or a chemical process. Dissociation is usually reversible.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.