monocyte Myeloid mononuclear recirculating leukocyte that can act as a precursor of tissue macrophages, osteoclasts and some populations of tissue dendritic cells. NCIt:C12547 A mononuclear phagocytic leukocyte, 13 to 25 mm in diameter, with an ovoid or kidney-shaped nucleus, containing lacy, linear chromatin and abundant gray-blue cytoplasm filled with fine reddish and azurophilic granules. Formed in the bone marrow from promonocytes, monocytes are transported to tissues such as the lung and liver, where they develop into macrophages. SNOMEDCT:55918008 true MSH:D009000 James Malone Tomasz Adamusiak myeloid leukocyte cell type