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[mon-uh-noo-klee-oh-sis, -nyoo-] /ˌmɒn əˌnu kliˈoʊ sɪs, -ˌnyu-/
noun, Pathology.
the presence of an abnormally large number of mononuclear leukocytes, or monocytes, in the blood.
Origin of mononucleosis
First recorded in 1915-20; mononucle(ar) + -osis Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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British Dictionary definitions for mononucleosis


(pathol) the presence of a large number of monocytes in the blood
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
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Word Origin and History for mononucleosis

1920, coined from mononuclear + Modern Latin -osis "abnormal condition."

Online Etymology Dictionary, © 2010 Douglas Harper
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mononucleosis in Medicine

mononucleosis mon·o·nu·cle·o·sis (mŏn'ō-nōō'klē-ō'sĭs, -nyōō-)

  1. Abnormally large numbers of mononuclear white blood cells in the blood, especially forms that are not normal.

  2. Infectious mononucleosis.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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mononucleosis in Science
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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mononucleosis in Culture
mononucleosis [(mon-uh-nooh-klee-oh-sis)]

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.

Note: 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.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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