I. ˈlābēəl adjective
Etymology: Medieval Latin labialis, from Latin labium lip + -alis -al — more at lip
1. : of or relating to the lips or labia
a labial gland
a labial scale
2. : giving its tones from impact of an air current on a lip or liplike edge
a labial instrument like the flute
3. : produced with the participation of one or both lips — used of consonants (as f, v, p, b) and of rounded vowels (as ü) and semivowels (as w); compare bilabial , labiodental
II. noun
( -s )
1. : flue pipe
2. : a labial consonant
3. : one of the small scales that border the lips of most snakes and many other reptiles