Callipygian

callipygian \ˌka-lə-ˈpi-j(ē-)ən\ also callipygous \-ˈpī-gəs\ adjective: having shapely buttocks

Etymology: Greek kallipygos, from kalli- beautiful + pygē buttocks

Calligraphy and kaleidoscope are also constructed from kallos, the ancient Greek word for beauty.