jowl vs lower jawbone

jowl and lower jawbone both are nouns.

Word	Noun	Adjective	Verb	Adverb
jowl	Yes	No	No	No
lower jawbone	Yes	No	No	No

As nouns, jowl and lower jawbone are synonyms defined as:

jowl and lower jawbone: the jaw in vertebrates that is hinged to open the mouth

Other synonyms of jowl include jawbone, lower jaw, mandible, mandibula, mandibular bone, submaxilla.

jowl (noun)	lower jawbone (noun)
the jaw in vertebrates that is hinged to open the mouth	the jaw in vertebrates that is hinged to open the mouth
a fullness and looseness of the flesh of the lower cheek and jaw (characteristic of aging)