hal·​lu·​ci·​na·​tion | \ hə-ˌlü-sə-ˈnā-shən \

Definition of hallucination

1a : perception of objects with no reality usually arising from disorder of the nervous system or in response to drugs (such as LSD) was having hallucinations
b : the object so perceived wasn't sure if the rain was real or a hallucination
2 : an unfounded or mistaken impression or notion : delusion

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Choose the Right Synonym for hallucination

delusion, illusion, hallucination, mirage mean something that is believed to be true or real but that is actually false or unreal. delusion implies an inability to distinguish between what is real and what only seems to be real, often as the result of a disordered state of mind. delusions of persecution illusion implies a false ascribing of reality based on what one sees or imagines. an illusion of safety hallucination implies impressions that are the product of disordered senses, as because of mental illness or drugs. suffered from terrifying hallucinations mirage in its extended sense applies to an illusory vision, dream, hope, or aim. claimed a balanced budget is a mirage

Examples of hallucination in a Sentence

He could not tell if what he was seeing was real or if it was a hallucination. He has been having hallucinations due to the medication.

Recent Examples on the Web

Someone experiencing psychosis has difficulty understanding what is real and usually experiences delusions (false beliefs) and hallucinations (seeing or hearing things that aren’t there). Carolyn L. Todd, SELF, "9 Things You Should Know About Taking Antipsychotic Drugs," 7 Dec. 2018 Two currents are constantly crossing in the stories, the first depicting the polite forms of public interactions and the second pulsing with taboo fantasies and hallucinations. Sam Sacks, WSJ, "Fiction: The Union of Death and Desire," 22 Nov. 2018 Betty brings up seeing Polly’s twins dropped into the fire and Alice and Polly write that off as a hallucination. Jessica Macleish, Teen Vogue, ""Riverdale" Recap Season 3 Episode 2: Betty and Jughead Have a New Mystery to Solve," 18 Oct. 2018 There's a difference between a vision and a hallucination, and time will tell with Tubbs. Steve Lopez, latimes.com, "Stockton's young mayor has bold turnaround plan: Basic income and stipends for potential shooters," 27 May 2018 His fever was soaring, and he was curled up in the corner experiencing what seemed like hallucinations, babbling incoherently. Lindsey Vehlewald, SELF, "We Never Got Flu Shots. Then the Flu Almost Killed My Husband," 9 Nov. 2018 The story, from the narrator’s curious vantage in limbo, wends inside Eden’s consciousness, reproducing his memories and imagining his perceptions from his new home in the burn center, throttled by pain and hallucinations. Sam Sacks, WSJ, "Fiction: When Nowhere Felt Like Home," 20 Sep. 2018 But their symptoms — foaming at the mouth, pinpoint pupils and hallucinations — were similar to those that had emerged with the three previous victims: the Skripals, and a detective who was exposed while responding to the crime. Ellen Barry, New York Times, "Dawn Sturgess, British Woman Poisoned by Novichok, Dies," 8 July 2018 For obvious reasons, Jack doesn’t share a lot of screen time with his adult children, but thanks to dream sequences and hallucinations there are rare exceptions. Emma Dibdin, Country Living, "'This Is Us' Recap: Jack and an Adult Kate Appeared Together for the First Time and It Was Emotional," 10 Oct. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hallucination.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of hallucination

1629, in the meaning defined at sense 1a

History and Etymology for hallucination

see hallucinate

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Last Updated

26 Dec 2018

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Time Traveler for hallucination

The first known use of hallucination was in 1629

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More Definitions for hallucination



English Language Learners Definition of hallucination

: something (such as an image, a sound, or a smell) that seems real but does not really exist and that is usually caused by mental illness or the effect of a drug


hal·​lu·​ci·​na·​tion | \ hə-ˌlü-sə-ˈnā-shən \

Kids Definition of hallucination

: the seeing of objects or the experiencing of feelings that are not real but are usually the result of mental disorder or the effect of a drug


hal·​lu·​ci·​na·​tion | \ hə-ˌlüs-ᵊn-ˈā-shən \

Medical Definition of hallucination

1 : a perception of something (as a visual image or a sound) with no external cause usually arising from a disorder of the nervous system (as in delirium tremens or in functional psychosis without known neurological disease) or in response to drugs (as LSD) — compare delusion sense 2, illusion sense 2a
2 : the object of a hallucinatory perception

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