mononucleosis

noun

mono·​nu·​cle·​o·​sis ˌmä-nə-ˌnü-klē-ˈō-səs 

-ˌnyü-

: 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

Cooper recalled getting over a case of mononucleosis during her collegiate soccer stint, one of many players on the team who had been infected at the time. —Skyler Caruso, People.com, 13 June 2025

But Becker, who missed much of last season with mononucleosis, is healthy and playing vital roles for the red-hot Patriots. —Bobby Narang, Chicago Tribune, 7 May 2025

Certain conditions, like tonsillitis and mononucleosis, or injuries may require more extensive therapy. —Mark Gurarie, Health, 17 Mar. 2025

Skin rashes, sudden allergies, hypersensitivity, and re-emerging latent viruses like the kind that cause mononucleosis and herpes are common among space crews. —Lauren Leffer, Popular Science, 27 Feb. 2025

Word History

Etymology

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

First Known Use

1902, in the meaning defined above

Phrases Containing mononucleosis

• infectious mononucleosis

Rhymes for mononucleosis

• actinomycosis
• atherosclerosis
• endometriosis
• erythematosus
• erythroblastosis
• granulomatosis
• hemochromatosis
• histiocytosis
• hyperkeratosis
• ketoacidosis
• osteonecrosis
• osteoporosis

Medical Definition

mononucleosis

noun

mono·​nu·​cle·​o·​sis -ˌn(y)ü-klē-ˈō-səs 

: an abnormal increase of mononuclear white blood cells in the blood

specifically : infectious mononucleosis