What is "ballet flat"

n. A type of women's flat with a very low heel, thin sole, and round toe.

Ballet flats or Dolly shoes are derived from a woman's soft ballet shoe, with a very thin heel or the appearance of no heel at all. The style sometimes features a ribbon-like binding around the low tops of the slipper and may have a slight gathering at the top-front of the vamp (toe box) and a tiny, decorative string tie. Ballet slippers can be adjusted and tightened to the wearer's foot by means of this string tie and done.