methemoglobinemia Syllabification: (met·he·mo·glo·bi·ne·mi·a)Pronunciation: /ˌmetˌhēməˌglōbəˈnēmēə/ (Britishmethaemoglobinaemia)Definition of methemoglobinemia noun Medicine the presence of methemoglobin in the blood. methemoglobinemia in other Oxford dictionaries Definition of methemoglobinemia in the British & World English dictionary