jowl vs lower jaw

jowl and lower jaw both are nouns.

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

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

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

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

jowl (noun)	lower jaw (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)