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fever

American  
[fee-ver] / ˈfi vər /

noun

  1. an abnormal condition of the body, characterized by undue rise in temperature, quickening of the pulse, and disturbance of various body functions.

  2. an abnormally high body temperature.

  3. the number of degrees of such a temperature above the normal.

  4. any of a group of diseases in which high temperature is a prominent symptom.

    scarlet fever.

  5. intense nervous excitement.

    The audience was in a fever of anticipation.

verb (used with object)

  1. to affect with or as with fever.

    The excitement fevered him.
fever British  
/ ˈfiːvə /

noun

  1. an abnormally high body temperature, accompanied by a fast pulse rate, dry skin, etc

  2. any of various diseases, such as yellow fever or scarlet fever, characterized by a high temperature

  3. intense nervous excitement or agitation

    she was in a fever about her party
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. (tr) to affect with or as if with fever

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
fever Scientific  
/ fē′vər /

  1. A body temperature that is higher than normal. Fever is the body's natural response to the release of substances called pyrogens by infectious agents such as bacteria and viruses. The pyrogens stimulate the hypothalamus in the brain to conserve heat and increase the basal metabolic rate.

fever Idioms  

  1. see cabin fever; run a fever.

Other Word Forms

  • fevered adjective
  • feverless adjective
  • unfevered adjective

Etymology

Origin of fever

First recorded before 1000; Middle English; Old English fefer, from Latin febr-, stem of febris; reinforced by Anglo-French fevre, Old French fievre, from Latin, as above

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Within 24 hours, Meg's symptoms - including a fever, headache, vomiting and a rash - had worsened.

From BBC • Apr. 3, 2026

No fever, no gastrointestinal distress, nothing resembling a cold, flu or Covid.

From The Wall Street Journal • Mar. 29, 2026

On a warm Sunday afternoon in February, the Huntington Library was packed with Lunar New Year festivities and early spring fever.

From Los Angeles Times • Mar. 27, 2026

It is no wonder the image of Cannavaro holding the trophy aloft at the Olympiastadion now feels like a fever dream to most Italians.

From BBC • Mar. 25, 2026

She’d been acting like Beefy with a fever: irrational, angry, immature.

From "Witchlings" by Claribel A. Ortega

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.