gibbous
adjective
gib·bous ˈji-bəs 
ˈgi-
ˈgi- 1
a
: marked by convexity or swelling
b
of the moon or a planet : seen with more than half but not all of the apparent disk illuminated
2
: having a hump : humpbacked
Did you know?
The adjective gibbous has its origins in the Latin noun gibbus, meaning "hump." It was adopted into Middle English to describe rounded, convex things. While it has been used to describe the rounded body parts of humans and animals (such as the back of a camel) and to describe the shape of certain flowers (such as snapdragons), the term is most often used to describe the moon: a gibbous moon is one that is between half full and full.
Example Sentences
Recent Examples on the Web Waxing gibbous moon: Most of the moon is now visible in the sky. 
Meghan Rose, Glamour, 1 Sep. 2022 Tonight a 98%-lit waning gibbous moon will rise later at night close to Neptune. Jamie Carter, Forbes, 7 Aug. 2022 An 82%-lit waning gibbous Moon will be between Saturn and Jupiter. Jamie Carter, Forbes, 10 July 2022 Tonight the waxing gibbous Moon will be close to Antares, the brightest star in the constellation of Scorpius. Jamie Carter, Forbes, 3 July 2022 Through binoculars or a telescope, a small gibbous appears: a mostly full Venus. Ethan Siegel, Forbes, 6 Sep. 2021 This year’s peak will take place under an unfavorable gibbous moon, but the shower should be strong enough for sky watchers to see some meteors. oregonlive, 2 Jan. 2022 The moon is unfortunately in a waxing gibbous phase on peak night, meaning that much of the moon will be visible. Megan Marples, CNN, 16 Nov. 2021 However, the waning gibbous Moon—tonight 98%-lit—will blot-out all but the very brightest bits of the great comet. Jamie Carter, Forbes, 17 Oct. 2021 See More
Meghan Rose, Glamour, 1 Sep. 2022 Tonight a 98%-lit waning gibbous moon will rise later at night close to Neptune. Jamie Carter, Forbes, 7 Aug. 2022 An 82%-lit waning gibbous Moon will be between Saturn and Jupiter. Jamie Carter, Forbes, 10 July 2022 Tonight the waxing gibbous Moon will be close to Antares, the brightest star in the constellation of Scorpius. Jamie Carter, Forbes, 3 July 2022 Through binoculars or a telescope, a small gibbous appears: a mostly full Venus. Ethan Siegel, Forbes, 6 Sep. 2021 This year’s peak will take place under an unfavorable gibbous moon, but the shower should be strong enough for sky watchers to see some meteors. oregonlive, 2 Jan. 2022 The moon is unfortunately in a waxing gibbous phase on peak night, meaning that much of the moon will be visible. Megan Marples, CNN, 16 Nov. 2021 However, the waning gibbous Moon—tonight 98%-lit—will blot-out all but the very brightest bits of the great comet. Jamie Carter, Forbes, 17 Oct. 2021 See More Word History
Etymology
Middle English, from Late Latin gibbosus humpbacked, from Latin gibbus hump
First Known Use
14th century, in the meaning defined at sense 1a
Medical Definition
gibbous
adjective
gib·bous ˈjib-əs ˈgib-
ˈgib- 1
: marked by swelling or convexity especially on one side : protuberant
2
: having a hump