Definition of labrum:
(n) :
(anatomy) Any of several lip-like projections.
(n) :
(entomology, zootomy) The uppermost of the mouthparts (trophi) of a typical insect, such as a cockroach. Typically resembles an upper lip and forms part of the roof of the mouth in such insects.
(n) :
A large basin of warm water, with an overhanging lip, in a Roman bath.
(n) :
A surname.