megakaryocyte vs bone cell

megakaryocyte and bone cell both are nouns.

Word	Noun	Adjective	Verb	Adverb
megakaryocyte	Yes	No	No	No
bone cell	Yes	No	No	No

As nouns, bone cell is a hypernym of megakaryocyte; that is, bone cell is a word with a broader meaning than megakaryocyte:

megakaryocyte: a large bone marrow cell; regarded as the source of blood platelets
bone cell: a cell that is part of a bone

megakaryocyte (noun)	bone cell (noun)
a large bone marrow cell; regarded as the source of blood platelets	a cell that is part of a bone