Source : Webster's Revised Unabridged Dictionary (1913)

Waistband \Waist"band\, n.
   1. The band which encompasses the waist; esp., one on the
      upper part of breeches, trousers, pantaloons, skirts, or
      the like.

   2. A sash worn by women around the waist. [R.]

Source : WordNet®

waistband
     n : a band of material around the waist that strengthens a skirt
         or trousers [syn: {girdle}, {cincture}, {sash}, {waistcloth}]