/ Dictionary / Index U umbonal: Meaning and Definition of Find definitions for: um•bo•nal Pronunciation: (um'bu-nl), [key] — adj. having the shape or appearance of an umbo; bosslike: an umbonal structure. of, pertaining to, or near the umbo: the umbonal region. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. umbo umbonate Related Content Daily Word Quiz: inane Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language