The gibbous shadows that could be seen on the horizon were those of oxen pulling plows.
“With a simple triangular sweep, you can see the clouds and moons of Jupiter, mountains and craters on the Moon, and the fat gibbous form of Venus.” - From a report on WKBN.com (Youngstown, Ohio), December 26, 2011
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.
From Merriam-Webster Online at www.Merriam-Webster.com.