第一的英語翻譯：

first; firstly; primary
【醫(yī)】 arch-; arche-; eka-; prot-; proto-
【經(jīng)】 no 1

磨牙的英語翻譯：

grind one's teeth; indulge in idle talk; molar
【醫(yī)】 axle-tooth; azzle-tooth; azzlz teeth; back teeth; brymus
dentes columellaris; dentes molares; grinder; jaw teeth
masticatory teeth; molar; molar teeth; mylodontes; mylodus
odontoprisis; triturating teeth; wall teeth