Any of the immature or mature forms of a granular leukocyte that in its mature form has an irregularly shaped, pale-staining nucleus that is partially constricted into two lobes, and with cytoplasm that contains coarse, bluish-black granules of variable size. Basophils contain vasoactive amines such as histamine and serotonin, which are released on appropriate stimulation. A basophil is CD123-positive, CD193-positive, CD203c-positive, and FceRIa-positive.