/ Dictionary / Index G gibbous: Meaning and Definition of Find definitions for: gib•bous Pronunciation: (gib'us), [key] — adj. (of a heavenly body) convex at both edges, as the moon when more than half full. See diag. under humpbacked. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gibbous (Thesaurus) gibbosity Gibbs Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language