dentifrice
n.
early 15c., from Middle French dentifrice (15c.), from Latin dentifricium "powder for rubbing the teeth," from dens (genitive dentis) "tooth" (see tooth) + fricare "to rub" (see friction).
〔李〕n.牙粉；牙膏 [fric=to rub] ←denti-，dento-[L] =tooth齿