A labial (from Latin labium " lip " ) is a sound in phonetics, at the articulation primarily the lips are involved. There are labiodental sounds ( articulation, the contact between the lower lip and the teeth of the upper jaw ), labio - labial ( bilabial ) Lute, are involved in the formation of which the upper and lower lip as well as apico - labial sounds. Apiko - labial sounds are available in some Caucasian languages . Here, the articulator, the tongue tip (apex) and the place of articulation is the upper lip.
In dentistry, the adjective describes the labial tooth surface lying on the lip, see location and direction designations to the teeth.