mandibula vs lower jaw

mandibula and lower jaw both are nouns.

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

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

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

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

mandibula (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