[ ih-loo-zhuhn ]
/ ɪˈlu ʒən /
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See synonyms for: illusion / illusions on Thesaurus.com

something that deceives by producing a false or misleading impression of reality.
the state or condition of being deceived; misapprehension.
an instance of being deceived.
Psychology. a perception, as of visual stimuli (optical illusion ), that represents what is perceived in a way different from the way it is in reality.
a very thin, delicate tulle of silk or nylon having a cobwebbed appearance, for trimmings, veilings, and the like.
Obsolete. the act of deceiving; deception; delusion.
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Origin of illusion

First recorded in 1300–50; Middle English from Latin illūsiōn- (stem of illūsiō ) “irony, mocking,” equivalent to illūs(us), past participle of illūdere “to mock, ridicule” (il- il-1 + lūd- play (see ludicrous) + -tus past participle suffix) + -iōn- -ion

synonym study for illusion

1. illusion, hallucination, delusion refer to false perceptions or ideas. An illusion is a false mental image produced by misinterpretation of things that actually exist: A mirage is an illusion produced by reflection of light against the sky. A hallucination is a perception of a thing or quality that has no physical counterpart: Under the influence of LSD, Terry had hallucinations that the living-room floor was rippling. A delusion is a persistent false belief: A paranoiac has delusions of persecution.


il·lu·sioned, adjective


1. allusion, elusion, illusion 2. delusion, hallucination, illusion (see synonym study at the current entry)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use illusion in a sentence

  • I wouldn't giv a cent for a man who hadn't bin illusioned, and who didn't expect tew be several times again.

    Josh Billings, Hiz Sayings|Henry Wheeler Shaw
  • He was himself too much of a player on the stage of American affairs to be illusioned by any mimic representation.

  • I think nothing else of importance happened during the day, but I was so illusioned with fever that I cannot be sure.

    Ladysmith|H. W. Nevinson

British Dictionary definitions for illusion

/ (ɪˈluːʒən) /

a false appearance or deceptive impression of realitythe mirror gives an illusion of depth
a false or misleading perception or belief; delusionhe has the illusion that he is really clever
psychol a perception that is not true to reality, having been altered subjectively in some way in the mind of the perceiverSee also hallucination
a very fine gauze or tulle used for trimmings, veils, etc

Derived forms of illusion

illusionary or illusional, adjectiveillusioned, adjective

Word Origin for illusion

C14: from Latin illūsiō deceit, from illūdere; see illude
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

Medical definitions for illusion

[ ĭ-lōōzhən ]

An erroneous perception of reality.
An erroneous concept or belief.
The condition of being deceived by a false perception or belief.
Something, such as a fantastic plan or desire, that causes an erroneous belief or perception.

Other words from illusion

il•lusion•al null adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.