Entry: gibbous (adj.)
In context: "And they both could feel this queer dry night-desert chill descend with the moon's gibbous rise - a powdery wind down below making dust to shift and cactus needles whistle, the sky's stars adjusting to the color of low flame - but were themselves not yet chilled, even Steeply's sleeveless dress: he and Marathe stood and sat in the form-fitting astral spacesuit of warmth their own radiant heat provided."
Definition: Astron. Said of the moon or a planet when the illuminated portion exceeds a semicircle, but is less than a circle.
Other: I'm curious to what/whom the author is referring:
1690 W. Leybourn Cursus Mathematicus f. 449, She is liable to the same variety of changes as the Moon, sometimes almost Full, at other times Gibbous.
SNOOT score: 2
Source: Oxford English Dictionary