Meaning of umbonal

um•bo•nal

Pronunciation: (um'bu-nl), [key]
— adj.
  1. having the shape or appearance of an umbo; bosslike: an umbonal structure.
  2. of, pertaining to, or near the umbo: the umbonal region.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.