gibbous

Etymology

From Middle English gibbous, from Latin gibbus (“humped, hunched”), probably cognate with cubō (“bend oneself, lie down”), Italian gobba (“humpback”), Greek κύφος (kýfos, “humpback, bent”), κύβος (kývos, “cube, vertebra”), Spanish giboso (“humped”). Also ultimately compare dialectal Norwegian keiv (“slanted, wrong”) and Dutch scheef (“crooked, slanting”).

adj

1. Characterized by convexity; protuberant.
2. (astronomy, of a celestial body) Having more than half (but not the whole) of its disc illuminated.
   On December 7, 1972, the Apollo 17 astronauts took a photograph of a gibbous Earth at a distance of eighteen thousand miles from its surface. 2021, Ruth Ozeki, The Book of Form and Emptiness, Canongate Books (2022), page 252
3. Humpbacked.