noun (n)

• the jaw in vertebrates that is hinged to open the mouth(noun.body)

  Synonym:
  jawbone, jowl, lower jaw, lower jawbone, mandibula, mandibular bone, submaxilla
  

  source: wordnet30
• The bone, or principal bone, of the lower jaw; the inferior maxilla; -- also applied to either the upper or the lower jaw in the beak of birds.(noun)

  source: webster1913