Labial \La"bi*al\, n.

1. (Phonetics) A letter or character representing an articulation or sound formed or uttered chiefly with the lips, as b, p, w.

2. (Mus.) An organ pipe that is furnished with lips; a flue pipe.

3. (Zo["o]l.) One of the scales which border the mouth of a fish or reptile.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Labial \La"bi*al\, a. [LL. labialis, fr. L. labium lip: cf. F. labial. See Lip.]

1. Of or pertaining to the lips or labia; as, labial veins.

2. (Mus.) Furnished with lips; as, a labial organ pipe.

3. (Phonetics)
   (a) Articulated, as a consonant, mainly by the lips, as b, p, m, w.
   (b) Modified, as a vowel, by contraction of the lip opening, as [=oo] (f[=oo]d), [=o] ([=o]ld), etc., and as eu and u in French, and ["o], ["u] in German. See Guide to Pronunciation, [sect][sect] 11, 178.

4. (Zo["o]l.) Of or pertaining to the labium; as, the labial palpi of insects. See Labium.

Source: Webster's Revised Unabridged Dictionary (1913)