noun.
A large blood-corpuscle, measuring from 12 to 15 micromillimeters in diameter, found in the human blood in cases of anemia, especially of pernicious anemia.
the GNU version of the Collaborative International Dictionary of English
noun.
A large, flattened red blood cell corpuscle having no nucleus, twice the diameter of the ordinary red corpuscle, found in considerable numbers in the blood in profound anæmia.