- Bustier (Bra) : Bustier refers to a bra style top that generally goes all the way to the Waist but may be Cropped or go to the hips. A bustier may have shoulder straps or be strapless. Bustiers may or may n ot have supportive boning and detachable garters. The purpose of a bustier is to provide a sexy top with bust support and shape to the waist. Sizes are usually based on the women's bra size.