granulocyte SNOMEDCT:256909001 Tomasz Adamusiak A leukocyte with abundant granules in the cytoplasm. A polymorphonuclear white blood cell with granule-containing cytoplasm. A polymorphonuclear white blood cell with granule-containing cytoplasm.nIn humans the granulocytes are also classified as polymorphonuclear leucocytes and are subdivided according to the staining properties of the granules into eosinophils, basophils and neutrophils, some invertebrate blood cells are also referred to, not very helpfully, as granulocytes. James Malone NCIt:C12530 myeloid leukocyte cell type