English Noun lower jaw (plural lower jaws) The part of the face below the mouth; the jaw. Specifically, the bone therein; the mandible of humans and other vertebrates that, with the cranium, composes the skull. Synonyms (part of the face below the mouth): underjaw (mandible): jawbone Translations part of the face below the mouth German: Unterkiefer (de) m, Kiefer (de) m Swedish: underkäke (sv) c mandible of humans and other vertebrates German: Unterkieferknochen (de) m Swedish: underkäke (sv) c, mandibel c See also dentary boneWikiwand - on Seamless Wikipedia browsing. On steroids.