An early form of a red blood cell, usually found only in bone marrow but occurring in the blood in some types of leukaemia and anaemia.
A nucleated cell that forms part of the series giving rise to the red blood cells and is normally found in the blood forming tissue of the bone marrow. Normoblasts pass through three stages of maturation: early (or basophilic), intermediate (or polychromatic), and late (or orthochromatic) forms.
The precursor of an erythrocyte which still contains the remnant of a nucleus.
An immature nucleated red blood cell similar in size to a mature erythrocyte and usually found in the bone marrow.