occipital bone vs membrane bone

occipital bone and membrane bone both are nouns.

Word	Noun	Adjective	Verb	Adverb
occipital bone	Yes	No	No	No
membrane bone	Yes	No	No	No

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

occipital bone: a saucer-shaped membrane bone that forms the back of the skull
membrane bone: any bone that develops within membranous tissue without previous cartilage formation; e.g. the clavicle and bones of the skull

occipital bone (noun)	membrane bone (noun)
a saucer-shaped membrane bone that forms the back of the skull	any bone that develops within membranous tissue without previous cartilage formation; e.g. the clavicle and bones of the skull