hal·​lu·​ci·​no·​sis | \ hə-ˌlü-sə-ˈnō-səs How to pronounce hallucinosis (audio) \

Definition of hallucinosis

: a pathological mental state characterized by hallucinations

Examples of hallucinosis in a Sentence

Recent Examples on the Web Boes was working with a patient who had a rare disorder called peduncular hallucinosis, in which damage to the thalamus, a structure at the center of the brain, causes visual hallucinations. Grace Huckins, Wired, "A Radical New Model of the Brain Illuminates Its Wiring," 17 Aug. 2020

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

First Known Use of hallucinosis

1905, in the meaning defined above

History and Etymology for hallucinosis

New Latin

Keep scrolling for more

Learn More about hallucinosis

Time Traveler for hallucinosis

Time Traveler

The first known use of hallucinosis was in 1905

See more words from the same year

Statistics for hallucinosis

Cite this Entry

“Hallucinosis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hallucinosis. Accessed 30 Nov. 2020.

Keep scrolling for more

More Definitions for hallucinosis


hal·​lu·​ci·​no·​sis | \ hə-ˌlüs-ᵊn-ˈō-səs How to pronounce hallucinosis (audio) \
plural hallucinoses\ -​ˌsēz How to pronounce hallucinoses (audio) \

Medical Definition of hallucinosis

: a pathological mental state characterized by hallucinations

More from Merriam-Webster on hallucinosis

Thesaurus: All synonyms and antonyms for hallucinosis

Comments on hallucinosis

What made you want to look up hallucinosis? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

A Thanksgiving Word Quiz

  • a traditional thanksgiving dinner
  • November comes from a word for which of the following numbers?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!