psychosis

noun

psy·​cho·​sis sī-ˈkō-səs How to pronounce psychosis (audio)
plural psychoses sī-ˈkō-ˌsēz How to pronounce psychosis (audio)
Synonyms of psychosisnext
: a serious mental illness (such as schizophrenia) characterized by defective or lost contact with reality often with hallucinations or delusions

Examples of psychosis in a Sentence

The patient suffers from some kind of psychosis.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Postpartum psychosis is a rare but serious medical emergency characterized by severe, rapid onset psychiatric episodes such as mania, depression or hallucinations. — Peter Charalambous, ABC News, 7 Aug. 2026 Her attorney said Clancy was experiencing extreme postpartum psychosis. — Mike Toole, CBS News, 6 Aug. 2026 Partway through the season, Straczynski noticed O’Hare developing symptoms of psychosis, including paranoid delusions. — Jp Mangalindan, Entertainment Weekly, 6 Aug. 2026 In people with personal or family history of psychotic disorders, taking psilocybin may increase the risk of psychosis. — Helen Carefoot, Flow Space, 5 Aug. 2026 See All Example Sentences for psychosis

Word History

Etymology

New Latin

First Known Use

1847, in the meaning defined above

Time Traveler
The first known use of psychosis was in 1847

Rhymes for psychosis

See All Rhymes for psychosis

Browse Nearby Words

psychosexuality
psychosis
psychosocial
See all Nearby Words

Cite this Entry

“Psychosis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/psychosis. Accessed 10 Aug. 2026.

Copy Citation

Kids Definition

psychosis

noun
psy·​cho·​sis sī-ˈkō-səs How to pronounce psychosis (audio)
plural psychoses -ˈkō-ˌsēz How to pronounce psychosis (audio)
: a serious mental illness marked by loss of or greatly lessened ability to test whether what one is thinking and feeling about the real world is really true

Medical Definition

psychosis

noun
psy·​cho·​sis sī-ˈkō-səs How to pronounce psychosis (audio)
plural psychoses -ˌsēz How to pronounce psychosis (audio)
: a serious mental illness (as schizophrenia) characterized by defective or lost contact with reality often with hallucinations or delusions
Last Updated: - Updated example sentences
Love words? Need even more definitions?

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

Popular in Grammar & Usage

See More

7 Pairs of Commonly Confused Words

Merriam-Webster’s Great Big List of Words You Love to Hate

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?
See More

Popular in Wordplay

See More

The Longest Long Words List

It's a Scorcher! Words for the Summer Heat

14 Phobias You Probably Haven't Heard Of

The Words of the Week - Aug. 7

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

7 Pairs of Commonly Confused Words

The Longest Long Words List

It's a Scorcher! Words for the Summer Heat
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
fridge-magnet-letters
Drop a Letter Quiz August 2026 Drop a letter from a word to make a totally diffe...
See All