system of macrophages vs mononuclear phagocyte system

system of macrophages and mononuclear phagocyte system both are nouns.

Word	Noun	Adjective	Verb	Adverb
system of macrophages	Yes	No	No	No
mononuclear phagocyte system	Yes	No	No	No

As nouns, system of macrophages and mononuclear phagocyte system are synonyms defined as:

system of macrophages and mononuclear phagocyte system: a widely distributed system of free and fixed macrophages derived from bone marrow

Other synonyms of system of macrophages include MPS.

system of macrophages (noun)	mononuclear phagocyte system (noun)
a widely distributed system of free and fixed macrophages derived from bone marrow	a widely distributed system of free and fixed macrophages derived from bone marrow