labium n.; pl. -bia [L. labium, lip] 1. A lip. 2. (ARTHRO: Cheli-cerata) In Araneae, the lower lip, forming the floor of the mouth cavity. 3. (ARTHRO: Crustacea) The metastoma. 4. (ARTHRO: Insecta) One of the mouth-part structures, the lower lip, composed of fused second maxillae; has been referred to as the tongue at a certain phase of development. 5. (MOLL) The inner lip of a univalve shell, the inner side of the aperture or columellar lip extending from the origin at the lip of the labrum and resting on the columella.
Was this article helpful?