leucocyte vs free phagocyte

leucocyte and free phagocyte both are nouns.

Word	Noun	Adjective	Verb	Adverb
leucocyte	Yes	No	No	No
free phagocyte	Yes	No	No	No

As nouns, free phagocyte is a hypernym of leucocyte; that is, free phagocyte is a word with a broader meaning than leucocyte:

leucocyte: blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system
free phagocyte: a phagocyte that circulates in the blood

Other hypernyms of leucocyte include blood cell, blood corpuscle, corpuscle.

leucocyte (noun)	free phagocyte (noun)
blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system	a phagocyte that circulates in the blood