Hallucination Meaning

/həˌluːsɪˈneɪʃən/
C1

Definition, CEFR level C1, pronunciation, examples, and quiz.

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nounA sensory perception of something that does not exist, often arising from disorder of the nervous system, as in delirium tremens.

nounThe act of hallucinating; a wandering of the mind; an error, mistake or blunder.

All you saw was a hallucination.
Was it a hallucination or a daydream?
I've never heard of a hallucination being so vivid and terrifying.
Synonyms:
Antonyms:
None
CEFR Practice Quiz
The patient's ____ made him see things that were not real.
CEFR Practice Quiz (Alternate)
The patient experienced a vivid ____ caused by the high fever, as he thought he saw giant insects on the ceiling.

Derives from the verb hallucinate, from Latin hallucinatus. Compare French hallucination. The first known usage in the English language is from Sir Thomas Browne.

"Hallucinations are always evidence of cerebral derangement and are common phenomena of insanity." — 1871, William Alexander Hammond, A Treatise on the Diseases of the Nervous System:
"The authorities said that the spinach had caused “possible food-related toxic reactions” with those affected experiencing symptoms including delirium, hallucinations, blurred vision, rapid heartbeat and fever." — 2022 December 18, Yan Zhuang, “How Can Tainted Spinach Cause Hallucinations?”, in The New York Times, →ISSN:
"This must have been the hallucination of the transcriber." — 1712 September 8 (Gregorian calendar), [Joseph Addison], “THURSDAY, August 29, 1712”, in The Spectator, number 470; republished in Alexander Chalmers, editor, The Spectator; a New Edition, […], volume V, New York, N.Y.: D[aniel] Appleton & Company, 1853, →OCLC:
"Chatbots even forget that they are a bot and experience "hallucinations", Meta's description for when a bot confidently says something that is not true." — 2022 August 8, Liam Tung, “Meta warns its new chatbot may forget that it's a bot”, in ZDNET:
"Hallucinations are about adhering to the truth; when A.I. systems get confused, they have a bad habit of making things up rather than admitting their difficulties." — 2022 December 16, Farhad Manjoo, “ChatGPT Has a Devastating Sense of Humor”, in The New York Times, →ISSN:

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CEFR Practice Quiz
The patient's ____ made him see things that were not real.
CEFR Practice Quiz (Alternate)
The patient experienced a vivid ____ caused by the high fever, as he thought he saw giant insects on the ceiling.

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