methaemoglobinaemiaPronunciation: /ˌmɛθiːməˌgləʊbɪˈniːmɪə, mɛtˌhiː-/ (US methemoglobinemia)Definition of methaemoglobinaemia noun [mass noun] Medicine the presence of methaemoglobin in the blood. methaemoglobinaemia in other Oxford dictionaries Definition of methaemoglobinaemia in the US English dictionary