gnathic (adj.)youdaoicibaDictYouDict[gnathic 词源字典]
"pertaining to the jaw," 1882, with -ic + Greek gnathos "jaw, cheek," properly "the lower jaw," from PIE root *genu- (2) "jawbone, chin" (see chin (n.)).[gnathic etymology, gnathic origin, 英语词源]