the GNU version of the Collaborative International Dictionary of English
adj. Of or pertaining to the jaw.
The Century Dictionary and Cyclopedia
Of or pertaining to the jaws; specifically, in craniometry, pertaining to the alveolus of the jaws; alveolar: as, the gnathic or alveolar index (which see, under craniometry). Also gnathal.
Word Usage
"The degree of projection of the jaws is determined by the gnathic or alveolar index, which represents the proportion between the basialveolar and basinasal lengths, thus: basialveolar length X 100/basinasal length56"