- Astronomy. (of a heavenly body) convex at both edges, as the moon when more than half full.
Also gib·bose [gib-ohs] /ˈgɪb oʊs/.
Origin of gibbous
1350–1400; Middle English < Latin gibbōsus humped, equivalent to gibb(a) hump + -ōsus -ous
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for gibbous
Steep and gibbous behind, becoming at length smooth and equal.The Mushroom, Edible and Otherwise
M. E. Hard
The night was clear, and a gibbous moon was high in the sky.Camp-fire and Wigwam
Edward Sylvester Ellis
The moon was gibbous in its approach to the full when the boat left Vicksburg.The Last of the Flatboats
George Cary Eggleston
The esculent variety, in Europe, is the common green or gibbous frog, the Rana esculenta of Linnus.
Over the top of the great ranges a gibbous moon rose slowly.Gold
- (of the moon or a planet) more than half but less than fully illuminated
- having a hunchback; hunchbacked
C17: from Late Latin gibbōsus humpbacked, from Latin gibba hump
Word Origin and History for gibbous
c.1400, "bulging, convex," from Late Latin gibbus "hunchbacked," from Latin gibbus "hump, hunch," of uncertain origin. Of the moon from early 15c.; also used from 15c. of hunchbacks.
Online Etymology Dictionary, © 2010 Douglas Harper
- Characterized by convexity; protuberant.
- Having a hump; humpbacked.
- More than half but less than fully illuminated. Used to describe the Moon or a planet. Compare crescent.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.