PNEUMOCYSTIS Meaning of PNEUMOCYSTIS in English [ ˌnju:mə(ʊ)'sɪstɪs ]■ noun Medicine a parasitic protozoan that can cause fatal pneumonia in people affected with immunodeficiency disease. [ Pneumocystis carinii .] Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004