Labrum
Labrum , noun
[Latin]
1.
A lip or edge, as of a basin.
2.
(a) (Zoology) An organ in insects and crustaceans covering the upper part of the mouth, and serving as an upper lip. See Illust. of Hymenoptera.
(b)
(Zoology) The external margin of the aperture of a shell. See Univalve.