Definition of mononucleosis in US English:



  • 1An abnormally high proportion of monocytes in the blood.

    • ‘Common benign causes include adenoviral illness in children, mononucleosis, and some pharmaceuticals, and these can usually be identified with a careful history and examination.’
    • ‘The flu gave way to mononucleosis and finally chronic fatigue syndrome, which sidelined him for several months.’
    • ‘These white blood cells help fight viral infections, and an increased number of ‘atypical’ lymphocytes usually indicates current infection with mononucleosis.’
    • ‘The pharyngitis and flu-like symptoms are difficult to distinguish from mononucleosis in older patients.’
    • ‘As a sophomore, a bout with mononucleosis and an injury limited his play to 29 games, in which he scored just three goals.’
    1. 1.1
      short for infectious mononucleosis
      Also called mono