Is “Gibbous” a Scrabble word?
Yes
GIBBOUS
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Gibbous
/ˈɡɪbəs/
adjective
1.Characterized by convexity; protuberant.
2.Phase of moon or planet between first quarter and full or between full and last quarter.
3.Humpbacked.