Definition of umbo

Definition of umbo
  1. umbo Noun A boss, or rounded elevation, or a corresponding depression, in a palate, disk, or membrane; as, the umbo in the integument of the larvæ of echinoderms or in the tympanic membrane of the ear.
  2. umbo Noun One of the lateral prominence just above the hinge of a bivalve shell.
  3. umbo Noun A bump or protrusion on the top of the cap.
  4. umbo Noun The boss of a shield, at or near the middle, and usually projecting, sometimes in a sharp spike.
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