gibbous

adjective

gib·​bous ˈji-bəs  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.

Examples of gibbous in a Sentence

Recent Examples on the Web

What to expect This year’s viewing of the Lyrids faces a significant challenge due to the brightness of the waxing gibbous Moon, which will be 96% full at the peak of the shower. —George Dvorsky / Gizmodo, Quartz, 16 Apr. 2024

Sky watchers will have to contend with a bright waxing gibbous moon during the most prolific phase of the shower. —Sarah Kuta, Smithsonian Magazine, 12 Apr. 2024

Friday saw a waxing gibbous moon at 99% illumination. —Jenna Prestininzi, Detroit Free Press, 24 Feb. 2024

However, the full moon will fall on October 17, which means a waning gibbous moon will compete with the shower at its peak. —Margaret Osborne, Smithsonian Magazine, 2 Jan. 2024

On December 21 and 22 nights, a waxing gibbous moon will drop by Jupiter. —Jamie Carter, Forbes, 30 Nov. 2023

While finding a dark location is preferred, there's not much us Earthlings can due to combat the glaring waning gibbous moon — so instead of spotting 100 to 150 meteors per hour, viewers in the Northern Hemisphere are more likely to catch 30 to 40 instead. —Skyler Caruso, Peoplemag, 29 Nov. 2023

For example, a waning crescent will form a full moon with a waxing gibbous, first-quarter moons and third-quarter moons will come together as a perfect whole, and so on. —Aliza Pelto, Women's Health, 10 Sep. 2023

Waxing gibbous The waxing gibbous is when the results of your manifestation endeavors will begin to appear. —Aliza Pelto, Women's Health, 17 Mar. 2023

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

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Kids Definition

gibbous

adjective

gib·​bous ˈjib-əs  ˈgib- 

: seen with more than half but not all of the disk lighted

gibbous moon

Medical Definition

gibbous

adjective

gib·​bous ˈjib-əs  ˈgib- 

1

: marked by swelling or convexity especially on one side : protuberant

2

: having a hump