noun

mononucleosis

mah-noh-noo-klee-OH-sis/ˌmɑːnəʊˌnuːkliˈəʊsɪs/

An infectious illness causing fever, fatigue, and swollen glands.

Mononucleosis often causes a sore throat along with fever and fatigue.

A visibly exhausted, feverish young adult receives an examination of swollen neck glands, combining the characteristic symptom cues of mononucleosis in one compact clinical scene.

Etymology

monoEnglishsingle

+nucleEnglishrelating to a nucleus

+osisLatinabnormal condition

“Single nucleus” describes the white blood cells behind the name. The illness was named for an abnormally high proportion of these cells in the blood, with -osis marking an abnormal condition.

In context

Jill Carnahan, MD7:05

if they get infectious mononucleosis that can set off a permanent change

190: Resiliency Radio with Dr. Jill: Manifestations of Mast Cell Activation (MCAS) in the Gut!

More examples

She misses several weeks of school because of mononucleosis.
Sharing drinks can spread the virus that causes mononucleosis.
His doctor recommends rest while he recovers from mononucleosis.

Similar words

mono: An informal, shortened name for the same illness.