Pronunciation : Um"bo, n.; pl. L. Umbones
Part of Speech : E.
Etymology : [L.]
Definition : 1. The boss of a shield, at or near the middle, and usually projecting, sometimes in a sharp spike.
2. A boss, or rounded elevation, or a corresponding depression, in a palate, disk, or membrane; as, the umbo in the integument of the larv? of echinoderms or in the tympanic membrane of the ear.
3. (Zo?l.)
Defn: One of the lateral prominence just above the hinge of a bivalve shell.
Umbos.
Source : Webster's Unabridged Dictionary, 1913