n.
any blood cell that contains a nucleus. In health there are three major subdivisions: granulocyte, lymphocyte and monocyte, which are involved in protecting the body against foreign substances and in antibody production. In disease, a variety of other types may appear in the blood, most notably immature forms of the normal red or white blood cells.
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leu·co·cyte (looґko-sīt) leukocyte.Medical dictionary. 2011.