upper jawbone vs upper jaw

upper jawbone and upper jaw both are nouns.

Word	Noun	Adjective	Verb	Adverb
upper jawbone	Yes	No	No	No
upper jaw	Yes	No	No	No

As nouns, upper jawbone and upper jaw are synonyms defined as:

upper jawbone and upper jaw: the jaw in vertebrates that is fused to the cranium

Other synonyms of upper jawbone include maxilla, maxillary.

upper jawbone (noun)	upper jaw (noun)
the jaw in vertebrates that is fused to the cranium	the jaw in vertebrates that is fused to the cranium