hallucination

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

• IPA^(key): /həˌluːsɪˈneɪʃən/

• Audio (UK)

  (file)

• Rhymes: -eɪʃən

hallucination (countable and uncountable, plural hallucinations)

1. A sensory perception of something that does not exist, often arising from disorder of the nervous system, as in delirium tremens.
   • 1871, William Alexander Hammond, A Treatise on the Diseases of the Nervous System

     Hallucinations are always evidence of cerebral derangement and are common phenomena of insanity.

   • 2022 December 18, Yan Zhuang, “How Can Tainted Spinach Cause Hallucinations?”, in The New York Times‎, ISSN 0362-4331:

     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.

2. The act of hallucinating; a wandering of the mind; an error, mistake or blunder.
   • 1712 September 9 (Gregorian calendar)​, Joseph Addison, “FRIDAY, 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 191120697:

     This must have been the hallucination of the transcriber.

3. (artificial intelligence) A confident but incorrect response given by an artificial intelligence.
   • 2022 August 8, Liam Tung, “Meta warns its new chatbot may forget that it's a bot”, in ZDNET‎:

     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 December 16, Farhad Manjoo, “ChatGPT Has a Devastating Sense of Humor”, in The New York Times‎, ISSN 0362-4331:

     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.

   • 2023 January 10, Cade Metz, “A.I. Is Becoming More Conversational. But Will It Get More Honest?”, in The New York Times‎, ISSN 0362-4331:

     It may tell you that the official currency of Switzerland is the euro (it’s actually the Swiss franc) or that Mark Twain’s Celebrated Jumping Frog of Calaveras County could not only jump but talk. A.I. researchers call this generation of untruths “hallucination.”

• negative hallucination

• hallucination at OneLook Dictionary Search
• “hallucination”, in Merriam-Webster Online Dictionary

Borrowed from Latin hallūcinātiō; synchronically analysable as halluciner +‎ -ation.

• ^{(mute h)} IPA^(key): /a.ly.si.na.sjɔ̃/

• Audio

  (file)

• Rhymes: -ɔ̃
• Homophone: hallucinations

hallucination f (plural hallucinations)

1. hallucination

• hallucinant
• hallucinatoire
• halluciné
• halluciner
• hallucinogène
• hallucinose

• Turkish: halüsinasyon

• “hallucination”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.