Meaning of umbo

um•bo

Pronunciation: (um'bō), [key]
— pl. um•bo•nes um•bos.
  1. a boss on a shield, as one at the center of a circular shield.
  2. any similar boss or protuberance.
  3. the beak of a bivalve shell; the protuberance of each valve above the hinge.
  4. the depressed area on the outer surface of the tympanic membrane.
  5. a blunt or rounded protuberance arising from a surface, as on a pine cone scale.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
See also: