a sensory experience of something that does not exist outside the mind, caused by various physical and mental disorders, or by reaction to certain toxic substances, and usually manifested as visual or auditory images.
the sensation caused by a hallucinatory condition or the object or scene visualized.
a false notion, belief, or impression; illusion; delusion.

Origin of hallucination

1640–50; < Latin hallūcinātiōn- (stem of (h)allūcinātiō) a wandering of the mind. See hallucinate, -ion
Related formshal·lu·ci·na·tion·al, hal·lu·ci·na·tive [huh-loo-suh-ney-tiv, -nuh-tiv] /həˈlu səˌneɪ tɪv, -nə tɪv/, adjectivenon·hal·lu·ci·na·tion, noun
Can be confusedallusion delusion elusion hallucination illusion (see synonym study at illusion)

Synonyms for hallucination

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hallucination

Contemporary Examples of hallucination

Historical Examples of hallucination

  • Absolute equality is an hallucination of the hunger-fever, nothing more.


    Theodor Hertzka

  • All at once, however, Claude fancied he was the victim of some hallucination.

    His Masterpiece

    Emile Zola

  • He could not believe that Spurling had ever come; it was all an hallucination.

    Murder Point

    Coningsby Dawson

  • The simple matter is, dear madam, you have been under a hallucination all along.

  • When he saw her approaching he always had a moment of hallucination.

    Within the Tides

    Joseph Conrad

British Dictionary definitions for hallucination



the alleged perception of an object when no object is present, occurring under hypnosis, in some mental disorders, etc
Derived Formshallucinational, hallucinative or hallucinatory, adjective
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 hallucination

in the pathological/psychological sense of "seeing or hearing something which is not there," 1640s, from Latin hallucinationem (nominative hallucinatio), from past participle stem of hallucinari (see hallucinate). Hallucination is distinct from illusion in not necessarily involving a false belief. Related: Hallucinations.

Online Etymology Dictionary, © 2010 Douglas Harper

hallucination in Medicine




False or distorted perception of objects or events with a compelling sense of their reality, usually resulting from a mental disorder or drug.
The objects or events so perceived.
Related formshal•luci•nate′ v.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

hallucination in Culture


A false perception that appears to be real, as when, for example, a man dying of thirst in a desert thinks that he sees a lake. (See also delusion.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.