mononucleosis

American  

[mon-uh-noo-klee-oh-sis, -nyoo-] / ˌmɒn əˌnu kliˈoʊ sɪs, -ˌnyu- /

noun

Pathology.

1. the presence of an abnormally large number of mononuclear leukocytes, or monocytes, in the blood.

2. infectious mononucleosis.

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mononucleosis British  

/ ˌmɒnəʊˌnjuːklɪˈəʊsɪs /

noun

1. pathol the presence of a large number of monocytes in the blood

2. See infectious mononucleosis

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mononucleosis Scientific  

/ mŏn′ō-no̅o̅′klē-ō′sĭs /

1. A common infectious disease usually affecting young people, caused by the Epstein-Barr virus and characterized by fever, sore throat, swollen lymph nodes, and fatigue. The symptoms may last for several weeks.

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mononucleosis Cultural  

1. An acute and infectious disease caused by a virus; its symptoms include fever, swelling of the lymph nodes, and general exhaustion. Mononucleosis gets its name from the kind of white blood cell (monocyte) that increases in number in the blood of persons who have the disease. There is no specific treatment, but sufferers usually recover within a few weeks.

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Discover More

Mononucleosis is sometimes called the “kissing disease,” because at one time the virus was thought to be transmitted by kissing. The virus can be found in the saliva of those who have the disease, so there may be some truth in the belief.

Etymology

Origin of mononucleosis

First recorded in 1915–20; mononucle(ar) + -osis

Example Sentences

During his second season, Darnold became a punchline when he had to miss three games with mononucleosis, commonly referred to as the “kissing disease.”

From The Wall Street Journal • Jan. 29, 2026

Knipe says he became interested in the biology of herpesviruses as an undergraduate while recovering from a bout of mononucleosis.

From Science Daily • Dec. 15, 2023

He was aware that he had risk factors for lymphoma, including an autoimmune disease and having had mono, or infectious mononucleosis, as a child.

From New York Times • May 20, 2023

He was horribly sick for the first two years, including hepatitis, herpes and mononucleosis, and was eventually diagnosed with stage-four lymphoma and Kaposi’s sarcoma.

From Los Angeles Times • Jan. 12, 2023

This was despite the fact that his Cal Tech grades left much to be desired, even considering his long bout with mononucleosis.

From "Double Helix" by James D. Watson