myelocyte vs leucocyte

myelocyte and leucocyte both are nouns.

Word	Noun	Adjective	Verb	Adverb
myelocyte	Yes	No	No	No
leucocyte	Yes	No	No	No

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

myelocyte: an immature leukocyte normally found in bone marrow
leucocyte: blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system

Other hypernyms of myelocyte include leukocyte, WBC, white blood cell, white blood corpuscle, white cell, white corpuscle.

myelocyte (noun)	leucocyte (noun)
an immature leukocyte normally found in bone marrow	blood cells that engulf and digest bacteria and fungi; an important part of the body's defense system