Pronunciation: (lā'brum, lab'rum),[key] —n., —pl.la•braPronunciation: (lā'bru, lab'ru).[key] 1. a lip or liplike part.
2. Zool. a. the anterior, unpaired member of the mouthparts of an arthropod, projecting in front of the mouth.
b. the outer margin of the aperture of a shell of a gastropod.
3. Anat.a ring of cartilage about the edge of a joint surface of a bone.
Pronunciation: (lā'brum),[key] —n., —pl.-braPronunciation: (-bru).[key]Archaeol. an ornamented bathtub of ancient Rome.