os frontale vs membrane bone

os frontale and membrane bone both are nouns.

Word	Noun	Adjective	Verb	Adverb
os frontale	Yes	No	No	No
membrane bone	Yes	No	No	No

As nouns, membrane bone is a hypernym of os frontale; that is, membrane bone is a word with a broader meaning than os frontale:

os frontale: the large cranial bone forming the front part of the cranium: includes the upper part of the orbits
membrane bone: any bone that develops within membranous tissue without previous cartilage formation; e.g. the clavicle and bones of the skull

os frontale (noun)	membrane bone (noun)
the large cranial bone forming the front part of the cranium: includes the upper part of the orbits	any bone that develops within membranous tissue without previous cartilage formation; e.g. the clavicle and bones of the skull