from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Characterized by convexity; protuberant.
  • adjective More than half but less than fully illuminated from the point of view of an observer. Used of phases of the moon or the planets.
  • adjective Archaic Having a hump; humpbacked.

from The Century Dictionary.

  • Having a hunch or protuberance on the back; hunched; humpbacked; crookbacked.
  • Specifically Swelling by a regular curve; convex, as the moon is when more than half and less than full, the illuminated part being then convex on both margins.
  • In botany, having a rounded protuberance at the side or base.
  • In zoology, convex but not regularly rounded; somewhat irregularly raised or swollen; protuberant; humped; gibbose.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Swelling by a regular curve or surface; protuberant; convex.
  • adjective obsolete Hunched; hump-backed.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective Characterized by convexity; protuberant.
  • adjective astronomy Phase of moon or planet between first quarter and full or between full and last quarter.
  • adjective Humpbacked.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective (used of the moon) more than half full
  • adjective characteristic of or suffering from kyphosis, an abnormality of the vertebral column


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English, bulging, from Late Latin gibbōsus, hunch-backed, from Latin gibbus, hump.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English, from Latin gibbus ("humped, hunched"), probably cognate with cubō ("bend oneself, lie down"), Italian gobba ("humpback"), Greek κύφος (kyphos, "humpback, bent"), κύβος (kybos, "cube, vertebra").


  • +Cap+ bright yellowish or orange color, 3 to 7 inches broad, convex, then flattened, gibbous, that is, more convex on one side than on the other; viscid, covered with woolly (floccose) scales, which often separate.

    Among the Mushrooms A Guide For Beginners

  • In one sense the likenesses were speaking -- that is, a gibbous balloon proceeded from the mouth of each figure, wherein the following dialogue was indicated.

    The Cock-House at Fellsgarth

  • Consider the following (from 'Ghost World') which not only features the only - in my knowledge - use of the word 'gibbous' in popular song, but rather beautifully captures a mood:

    Word Magazine - Comments

  • Consider the following (from 'Ghost World') which not only features the only - in my knowledge - use of the word 'gibbous' in popular song, but rather beautifully captures a mood:

    Word Magazine -

  • There's a bewildering array of familiar supervillains and splendid interludes played as Catwoman, along with collectibles, side missions and distractions in a game that oozes the very essence of Batman, from dialogue and character design to the gibbous moon permanently silhouetting its buildings.

    This week's new games

  • This great democracy of ours is definitely waning, and it remains to be seen whether it will remain in its current gibbous state for long.

    Rizwan A. Rahmani: The Indifference of Younger Voters and Our Imperiled Democracy

  • Catch it 6° below-left of the earthlit crescent Moon on the 26th when its gibbous disc is 15 arcsec across.

    Starwatch: The January night sky

  • I wondered if a gibbous moon makes a gibbon speak gibberish?

    Myrtle Beach Daze

  • During February, it brightens from mag -4.1 to -4.2 and its gibbous disc swells from 15 to 18 arcsec.

    Starwatch: The February night sky

  • But a bright, gibbous moon would have cleared the hillside to shine into Mary Shelley's bedroom window just before 2am on 16 June.

    Frankenstein's hour of creation identified by astronomers


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  • also describing the 3/4 full moon

    December 1, 2007

  • "... the full moon, yellow and gibbous, came up out of an overflow of silver light in the north-east."

    - H.G. Wells, The Time Machine

    December 17, 2008

  • Opposite of crescent. Collocates with wax and wane.

    December 23, 2008

  • Exactly — I'm very puzzled by Wells' use of it here. A full moon is a full moon.

    OED: "c. Astr. Said of the moon or a planet when the illuminated portion exceeds a semicircle, but is less than a circle."

    December 23, 2008

  • I hadn't picked up on that. Maybe he was thinking of the fourth definition, about the bulge.

    December 23, 2008

  • I remember frowning at that line from Wells as I was reading The Time Machine recently. Assuming it wasn't just an error, I can only think that Wells was trying to convey a sense of the moon's looking distended or distorted, as it sometimes does under hazy conditions or when you're drunk.

    December 24, 2008

  • For us in 2008, it really only has one meaning. But maybe in his day another meaning was primary, or at least fairly well represented in the mix? (Trying to be generous.)

    December 24, 2008

  • Now, four days from the full moon (waxing gibbous), we were reduced to water, black coffee, liquor, cigarettes. From "The Last Werewolf" by Glen Duncan.

    March 18, 2012