eosinophiliaPronunciation: /ˌiːə(ʊ)ˌsɪnəˈfɪliə/Definition of eosinophilia noun [mass noun] Medicine an increase in the number of eosinophils in the blood, occurring in response to some allergens, drugs, and parasites, and in some types of leukaemia. eosinophilia in other Oxford dictionaries Definition of eosinophilia in the US English dictionary