Thalia, Aglaia and Euphrosyne, in myth (6)
I believe the answer is:
graces
(Other definitions for graces that I've seen before include "Three sister goddesses who have the power to grant beauty, charm and happiness." , "(Three) sister goddesses famed for their beauty" , "In Greek myth, three beautiful goddesses" , "In Greek myth, the three goddesses of beauty" , "Three Greek goddesses of beauty, charm and skill" .)