[gib-uh s]


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
Related formsgib·bous·ly, gib·bose·ly, adverbgib·bous·ness, gib·bose·ness, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for gibbous

British Dictionary definitions for gibbous


gibbose (ˈɡɪbəʊs)


(of the moon or a planet) more than half but less than fully illuminated
having a hunchback; hunchbacked
Derived Formsgibbously, adverbgibbousness, noun

Word Origin for gibbous

C17: from Late Latin gibbōsus humpbacked, from Latin gibba hump
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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

Medicine definitions for gibbous




Characterized by convexity; protuberant.
Having a hump; humpbacked.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for gibbous



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.