The traditional Belly Dancer costume usually consists of fitted leading or bra, a fitted hip belt, and a skirt or harem pants.
Belly Dancer Harem pants are usually very full and loose at the crotch / hips area and gathered in the ankle. This shape of the Harem pants is of Indian origin and the design helps in the free flow of movements while doing your belly dancing routine. However modern designs have been more progressive, leaving the loose trim at the hip area for a more fit trim and loose at the bottom. These modern design Harem pants costume for Belly dancers may not be "harem" in traditional sense yet it still serves its purpose. Moreover the use of Lycra or spandex in the manufacture of these modern Harem pants has retained its flexibility and has made it comfortable to wear and free flowing even while dancing.