comb (n.)youdaoicibaDictYouDict[comb 词源字典]
Old English camb "comb, crest, honeycomb" (later Anglian comb), from Proto-Germanic *kambaz (cognates: Old Saxon and Old High German camb, German Kamm, Middle Dutch cam, Dutch kam, Old Norse kambr), literally "toothed object," from PIE *gombhos, from root *gembh- "to bite, tooth" (cognates: Greek gomphos "a molar tooth," Sanskrit gambha-s "tooth").[comb etymology, comb origin, 英语词源]
grinder (n.)youdaoicibaDictYouDict
Old English grindere "one who grinds (grain);" agent noun from grind (v.). Meaning "molar tooth" is late 14c. (Old English had grindetoð). Meaning "machine for milling" is from 1660s; of persons, from late 15c. "Large sandwich" sense is from 1954, American English, though the exact signification is uncertain (perhaps from the amount of chewing required to eat one).
premolar (n.)youdaoicibaDictYouDict
"premolar tooth," 1841, from pre- + molar. Related: Premolars.