glandular fever
noun🔊/ˌɡlændʒələ ˈfiːvə(r)/
🔊/ˌɡlændʒələr ˈfiːvər/
(British English) (North American English mononucleosis, informal mono)
[uncountable]a disease that causes the lymph glands to swell (= become large, round and painful) and makes the person feel very weak for a long time