The Collaborative International Dictionary of English v.0.48:

Peplum \Pep"lum\, n.; pl. E. -lumus, L. -la. [L.]
   A peplos. Hence: An overskirt hanging like an ancient peplos;
   also, a short fitted skirt attached to a waist or coat.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

peplum
    n 1: a flared ruffle attached to the waistline of a dress or
         jacket or blouse
    2: a garment worn by women in ancient Greece; cloth caught at
       the shoulders and draped in folds to the waist [syn:
       peplos, peplus, peplum]