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Definition of "umbo" [um•bo]

  • The boss or knob at the center of a shield. (noun)
  • Biology A knoblike protuberance arising from a surface, as the prominence near the hinge of a bivalve shell or the projection at the scale tip of a seed-bearing cone. (noun)
  • Anatomy A small projection at the center of the outer surface of the eardrum. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Use "umbo" in a sentence
  • "Running upward and slightly forward from the umbo is a reddish-yellow streak produced by the manubrium of the malleus."
  • "For example, these bivalve shells, probably arks (Arcidae), each had a hole thru its umbo."
  • "For example, these bivalve shells, probably arks Arcidae, each had a hole thru its umbo."