“Polymorphonuclear leukocyte: A type of immune cell that has granules (small particles) with enzymes that are released during infections, allergic reactions, and asthma. Neutrophils, eosinophils, and basophils are polymorphonuclear leukocytes. A polymorphonuclear leukocyte is a type of white blood cell. Also called granular leukocyte, granulocyte, and PMN.
** PMNs aren’t just neutrophils, they are neutrophils + eosinophils + basophils. However, neutrophils are overwhelmingly usually the majority.
Mast cells are granulocytes as well. The contain basophilic granules.
http://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=633963