Definition of labial in English:

labial

adjective

  • 1Anatomy
    Relating to the lips.

    1. 1.1Dentistry (of the surface of a tooth) adjacent to the lips.
      • ‘The P4 has a small parastyle and the labial side of this tooth is longer than the lingual side.’
      • ‘Enamel is confined to the anterior and labial surface of the crown.’
      • ‘The lingual part of the transverse valley is slightly deeper than the labial part.’
      • ‘The labial and lingual surfaces are either more or less smooth, or covered with fine anastomosing striae.’
      • ‘The crests of the ectoloph run to stylar cusps on the labial side of the tooth.’
      • ‘Ankylosis is normally on the labial side of the tooth only, or on the labial side and at the bottom of the groove.’
    2. 1.2Zoology Resembling or serving as a lip, lip-like part, or labium.
      • ‘The paracone is the largest labial cusp, up to twice the height of the parastyle; the cusps posterior to it decrease evenly in size.’
      • ‘The organic particles are separated by size in sorting areas on the labial palps and are then directed into the mouth.’
      • ‘Expression is seen, however, in the tips of the antennae, maxillary and labial palps, and legs.’
      • ‘The only external structures are the labial palps; in some groups, there are sensory tentacles and photoreceptors at the edge of the mantle.’
      • ‘Moreover, the labial cusps of Desmatodon are not as strongly developed as those in Diadectes.’
  • 2Phonetics
    (of a consonant) requiring partial or complete closure of the lips (e.g. p, b, f, v, m, w), or (of a vowel) requiring rounded lips (e.g. oo in moon).

    • ‘That seems to be a complete invention, as both the sound and the video seem to me to indicate that there is a final labial consonant.’

noun

Phonetics
  • A labial sound.

    • ‘I guess that the great typological difference in the use of labials can speak for the great genetic difference in AmerIndian languages.’
    • ‘Thus, the broad versus slender contrast may, in the weak voiced labials, be labelled as ‘w versus v’, but in the strong voiced labials as ‘round b versus spread b’.’
    • ‘Chapter 4 describes cases where coronals undergo assimilation but dorsals and labials do not.’

Origin

Late 16th century: from medieval Latin labialis, from Latin labium lip.

Pronunciation:

labial

/ˈleɪbɪəl/