gibbous

adjective
gib·​bous | \ ˈji-bəs How to pronounce gibbous (audio) , ˈgi- How to pronounce gibbous (audio) \

Definition of gibbous

1a : 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

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Did You Know?

The adjective "gibbous" has its origins in the Latin noun gibbus, meaning "hump," and in the Late Latin adjective gibbosus, meaning "humpbacked," which Middle English adopted in the 14th century as "gibbous." "Gibbous" has been used to describe the rounded body parts of humans and animals (such as the back of a hunchback or camel) or to describe the shape of certain flowers (such as snapdragons). The term is most often identified, however, with the study of astronomy. In fact, if you run across the word gibbous, chances are you'll find the word moon somewhere nearby. A gibbous moon is one that is more than a half-moon but less than full.

Examples of gibbous in a Sentence

Recent Examples on the Web Over the weekend, the bright waning gibbous moon lit up the sky, which may have limited visibility, according to EarthSky. N'dea Yancey-bragg, USA TODAY, "Skwatchers capture dazzling photos of the Quadrantids, the first meteor shower of 2021," 4 Jan. 2021 Even if the skies are clear of clouds, a nearly full waning gibbous moon continues to shine brightly throughout the weekend, making meteor-spotting tricky. Sophie Lewis, CBS News, "The first meteor shower of 2021 will illuminate the night sky on New Year's weekend," 2 Jan. 2021 Even if the skies are clear of clouds, a nearly full waning gibbous moon will continue to shine brightly throughout the weekend, making meteor-spotting tricky. Sophie Lewis, CBS News, "The first meteor shower of 2021 will illuminate the night sky on New Year's weekend," 30 Dec. 2020 Lyrids meteor shower, with a waxing gibbous moon hanging bright in the sky. oregonlive, "Stargazing calendar 2021: Eclipses, meteor showers and other astronomical events this year," 30 Dec. 2020 Look toward the low eastern sky Thursday for the waning gibbous moon to form a celestial triangle with the twin stars Castor and Pollux (pictured above). National Geographic, "Will inertia rule America's course for now?," 4 Nov. 2020 Tomorrow and Friday evening, the waxing gibbous moon makes an impressive close approach with Jupiter and Saturn, which will be appearing in the constellation Sagittarius. National Geographic, "How do we come to grips with 200,000 dead?," 23 Sep. 2020 The full moon is a conspicuous ornament painted on the bowl of the sky, but a crescent, half, or gibbous moon is a three-dimensional ball suspended in space, a realization that still blows my mind a little bit every time. Nicole Clausing, Sunset Magazine, "Good Moon Rising," 24 Sep. 2020 Sky-watchers can see the waning gibbous moon and Mars rise in the east together in evening skies this weekend. National Geographic, "Why has it been so hard to let brilliant women shine?," 2 Sep. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'gibbous.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of gibbous

14th century, in the meaning defined at sense 1a

History and Etymology for gibbous

Middle English, from Late Latin gibbosus humpbacked, from Latin gibbus hump

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Time Traveler for gibbous

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The first known use of gibbous was in the 14th century

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Last Updated

21 Jan 2021

Cite this Entry

“Gibbous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/gibbous. Accessed 2 Mar. 2021.

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More Definitions for gibbous

gibbous

adjective
gib·​bous | \ ˈjib-əs How to pronounce gibbous (audio) , ˈgib- How to pronounce gibbous (audio) \

Medical Definition of gibbous

1 : marked by swelling or convexity especially on one side : protuberant
2 : having a hump : humpbacked

Comments on gibbous

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