buccal (adj.)

French, literally "mouth" (Old French boche, 11c.), from Latin bucca "cheek," which in Late Latin replaced os (see oral) as the word for "mouth" (and also is the source of Italian bocca, Spanish boca). De Vaan writes that "The meaning 'mouth' is secondary, and was originally used in a derogatory way." It is perhaps from Celtic, Germanic, or a non-IE substrate language.

The French word was borrowed in English in various senses, such as "king's allowance of food for his retinue" (mid-15c.); "mouth" (1580s); "metal plug for a cannon's vent" (1862; the verb in this sense is from 1781).