Douglas Harper's Etymology Dictionary
"of, pertaining to, or having beautiful buttocks," 1800, Latinized from Greek kallipygos, name of a statue of Aphrodite at Syracuse, from kalli-, combining form of kallos "beauty" (see Callisto) + pyge "rump, buttocks." Sir Thomas Browne (1646) refers to "Callipygæ and women largely composed behinde."
Wiktionary
a. Having beautifully shaped buttocks.
WordNet
adj. pertaining to or having finely developed buttocks; "the quest for the callipygian ideal" [syn: callipygous]
Usage examples of "callipygian".
She was no slender girl, but a woman of curves, a callimastean and callipygian marvel to put hunger in any man's eyes.
Helen America glanced back with an encouraging smile, her callipygian hips swaying beneath the Confederate cloak and the tattered muslin of her remarkable stage-garment.
Helen America glanced back with an encouraging smile, her callipygian hips swaying beneath the Confederate cloak and the tattered muslin of her remarkable stagegarment.