WBC vs free phagocyte

WBC and free phagocyte both are nouns.

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

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

WBC: 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 WBC include blood cell, blood corpuscle, corpuscle.

WBC (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