mono·​nu·​cle·​o·​sis | \ ˌmä-nə-ˌnü-klē-ˈō-səs How to pronounce mononucleosis (audio) , -ˌnyü- \

Definition of mononucleosis

: an abnormal increase of mononuclear white blood cells in the blood specifically : infectious mononucleosis

Examples of mononucleosis in a Sentence

Recent Examples on the Web But, particularly Darnold, who missed three games last season while dealing with mononucleosis. Dennis Waszak Jr.,, "Bell says Jets need healthy Darnold, so tells QB: ‘No bars’," 24 Aug. 2020 Many long-haulers are experiencing post-viral symptoms similar to those caused by mononucleosis and myalgic encephalomyelitis/chronic fatigue syndrome. Margot Gage Witvliet, The Conversation, "I’m a COVID-19 long-hauler and an epidemiologist – here’s how it feels when symptoms last for months," 11 Aug. 2020 Other herpes viruses, such as Epstein Barr virus, the cause of mononucleosis, and cytomegalovirus, which is a particular problem in immunodeficient individuals, can also emerge after latency. William Petri, The Conversation, "Does coronavirus linger in the body? What we know about how viruses in general hang on in the brain and testicles," 31 July 2020 Rose caught mononucleosis in April 2018 forcing the junior to miss a week of baseball play. Dennis Victory, al, "Bob Jones’ Caden Rose selected Huntsville Region Male Athlete of the Year," 20 June 2020 Many viral illnesses—including chickenpox, measles and mononucleosis—are accompanied by telltale skin rashes, often a result of the body’s heightened inflammatory response while fighting off infection. Jamie Ducharme, Time, "From 'COVID Toes' to Hives, These Are the Skin Conditions Dermatologists Think Could Be Signs of Coronavirus," 28 Apr. 2020 Broughton had his rookie season cut short because of a lingering bout with mononucleosis. Jeff Miller, Los Angeles Times, "Powerful veteran Linval Joseph should improve Chargers’ interior pass rush," 12 Apr. 2020 She was sidelined for the majority of the season with mononucleosis. Jenna Ciccotelli,, "Hannah Keating, HPNA find winning combination," 28 Jan. 2020 The Jets, meanwhile, are finally settled at quarterback now that Sam Darnold has recovered from a case of mononucleosis that forced him to miss three games., "That doesn’t mean it will happen, and the Patriots certainly deserve to be strong favorites coming into the “Monday Night Football” matchup at MetLife Stadium. But the Patriots have at least a few cracks in the foundation that are worth noting.," 21 Oct. 2019

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

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First Known Use of mononucleosis

1907, in the meaning defined above

History and Etymology for mononucleosis

New Latin, from International Scientific Vocabulary mononuclear + New Latin -osis

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Time Traveler for mononucleosis

Time Traveler

The first known use of mononucleosis was in 1907

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Last Updated

31 Aug 2020

Cite this Entry

“Mononucleosis.” Dictionary, Merriam-Webster, Accessed 27 Sep. 2020.

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How to pronounce mononucleosis (audio)

English Language Learners Definition of mononucleosis

medical : a disease that makes people very tired and weak for a long time


mono·​nu·​cle·​o·​sis | \ -ˌn(y)ü-klē-ˈō-səs How to pronounce mononucleosis (audio) \

Medical Definition of mononucleosis

: an abnormal increase of mononuclear white blood cells in the blood specifically : infectious mononucleosis

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