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illusion

[ih-loo-zhuh n] /ɪˈlu ʒən/
noun
1.
something that deceives by producing a false or misleading impression of reality.
2.
the state or condition of being deceived; misapprehension.
3.
an instance of being deceived.
4.
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.
5.
a very thin, delicate tulle of silk or nylon having a cobwebbed appearance, for trimmings, veilings, and the like.
6.
Obsolete. the act of deceiving; deception; delusion.
Origin
1300-1350
1300-50; Middle English < 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, with dt > s) + -iōn- -ion
Related forms
illusioned, adjective
Can be confused
allusion, delusion, elusion, hallucination, illusion (see synonym study at the current entry)
Synonyms
1. aberration, fantasy, chimera. 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.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for illusion
  • Since a rainbow is an optical illusion, it doesn't have an actual endpoint.
  • What hurts us is an illusion of knowledge that is empirically false.
  • He gives you illusion that has the appearance of truth.
  • The vanishing-edge pool creates the illusion that it could slip from its moorings and glide away.
  • Individual concrete pads create the illusion that they're hovering lightly above the desert floor.
  • In fact, it is the one illusion that makes every other perceptual illusion possible.
  • Self-aware, self-guiding consciousness did not exist, except as an illusion.
  • Moreover, they give the illusion that something constructive is being done.
  • Fortunately, these days the little spitfire's rarity is an illusion.
  • Trampling could even create the illusion of ancient sites where none really existed.
British Dictionary definitions for illusion

illusion

/ɪˈluːʒən/
noun
1.
a false appearance or deceptive impression of reality: the mirror gives an illusion of depth
2.
a false or misleading perception or belief; delusion: he has the illusion that he is really clever
3.
(psychol) a perception that is not true to reality, having been altered subjectively in some way in the mind of the perceiver See also hallucination
4.
a very fine gauze or tulle used for trimmings, veils, etc
Derived Forms
illusionary, illusional, adjective
illusioned, adjective
Word Origin
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
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Word Origin and History for illusion
n.

mid-14c., "act of deception," from Old French illusion "a mocking, deceit, deception" (12c.), from Latin illusionem (nominative illusio) "a mocking, jesting, irony," from illudere "mock at," literally "to play with," from assimilated form of in- "at, upon" (see in- (2)) + ludere "to play" (see ludicrous). Sense of "deceptive appearance" developed in Church Latin and was attested in English by late 14c. Related: Illusioned "full of illusions" (1920).

Online Etymology Dictionary, © 2010 Douglas Harper
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illusion in Medicine

illusion il·lu·sion (ĭ-lōō'zhən)
n.

  1. An erroneous perception of reality.

  2. An erroneous concept or belief.

  3. The condition of being deceived by a false perception or belief.

  4. Something, such as a fantastic plan or desire, that causes an erroneous belief or perception.


il·lu'sion·al or il·lu'sion·ar'y (-zhə-něr'ē) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Article for illusion

a misrepresentation of a "real" sensory stimulus-that is, an interpretation that contradicts objective "reality" as defined by general agreement. For example, a child who perceives tree branches at night as if they are goblins may be said to be having an illusion. An illusion is distinguished from a hallucination, an experience that seems to originate without an external source of stimulation. Neither experience is necessarily a sign of psychiatric disturbance, and both are regularly and consistently reported by virtually everyone.

Learn more about illusion with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Nearby words for illusion