\La"brum\, n.; pl. L. {Labra}, E. {Labrums}. [L.]
1. A lip or edge, as of a basin.
2. (Zo["o]l.)
   (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}.