cancer of the blood, leucaemia, leukaemia, leukemia - malignant neoplasm of blood-forming tissues; characterized by abnormal proliferation of leukocytes; one of the four major types of cancer

acute myelocytic leukemia, acute myeloid leukemia - acute leukemia characterized by proliferation of granular leukocytes; most common in adolescents and young adults

chronic myelocytic leukemia, myeloid leukemia - chronic leukemia characterized by granular leukocytes; more common in older people