LA'BIAL, adjective [Latin labium, a lip. See Lip.] Pertaining to the lips; formed by the lips; as a labial articulation. Thus b, p, and m are labial articulations. LA'BIAL, noun A letter or character representing an articulation of the lips; as b, f, m, p, v.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI