MONONUCLEOSIS Meaning of MONONUCLEOSIS in English [ ˌmɒnə(ʊ)nju:klɪ'əʊsɪs ]■ noun Medicine an abnormally high proportion of monocytes in the blood, especially associated with glandular fever. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004