Medical Definition of Neutrophil. Neutrophil: A type of white blood cell, a granulocyte that is filled with microscopic granules, little sacs containing enzymes that digest microorganisms. Also known as polymorphonuclear leukocyte or poly.
Definition of Neutropenia. Neutropenia: Not enough neutrophils, neutrophils being a type of white blood cell (specifically a form of granulocyte) filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis.
Neutropenia is a blood disorder that can affect anyone. Some people are born with it. It can happen after a viral infection. In some cases the cause can be a side effect of a drug, or exposure to certain poisons. People can get neutropenia when treated for cancer with chemotherapy drugs.