is the term used to refer to objects that are readily staining
with an azure dye
The term is used especially in reference to certain cytoplasmic granules in white blood cells, particularly hyperchromatin and reddish purple granules of certain blood cells.
As another example, neutrophils carry an arsenal of anti-microbial defensins within their azurophils, which eventually fuse with phagocytic vacuoles.
Contents include myeloperoxidase, defensins, neutral serine proteases, lysozyme, and bactericidal/permeability increasing protein.