Labrum

‖n.; pl. L. Labra E. Labrums [ L. ] 1. A lip or edge, as of a basin. [ 1913 Webster ]

2. (Zool.) (a) An organ in insects and crustaceans covering the upper part of the mouth, and serving as an upper lip. See Illust. of Hymenoptera. (b) The external margin of the aperture of a shell. See Univalve. [ 1913 Webster ]