What is defined as the lower jaw or jawbone?

The mandible is specifically defined as the lower jaw or jawbone in human anatomy. It is the largest and strongest bone in the face, playing a crucial role in both the structure of the jaw and in the mechanics of chewing. The mandible connects to the skull at the temporomandibular joints near the front of the ear, allowing for a wide range of movements necessary for biting and grinding food.

In contrast, the maxilla refers to the upper jawbone, which supports the upper teeth and forms part of the orbit of the eye. The palatine bones are located at the back of the oral cavity and contribute to the structure of the roof of the mouth as well as parts of the nasal cavity and eye sockets. The tongue, while essential for many functions such as tasting, swallowing, and articulation, does not refer to any part of the jaw structure itself. Thus, the mandible is the correct answer as it is directly defined as the lower jawbone.