Um"bo (?), n.; pl. L. Umbones (#), E. Umbos (#). [L.]


The boss of a shield, at or near the middle, and usually projecting, sometimes in a sharp spike.


A boss, or rounded elevation, or a corresponding depression, in a palate, disk, or membrane; as, the umbo in the integument of the larvae of echinoderms or in the tympanic membrane of the ear.

3. Zool.

One of the lateral prominence just above the hinge of a bivalve shell.


© Webster 1913.

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