The Collaborative International Dictionary of English v.0.48:

Smokeless powder \Smoke"less pow"der\
   A high-explosive gunpowder whose explosion produces little,
   if any, smoke. It is usually based on guncotton.
   [Webster 1913 Suppl. +PJC]

WordNet (r) 3.0 (2006):

smokeless powder
    n 1: an explosive (trade name Ballistite) that burns with
         relatively little smoke; contains pyrocellulose and is used
         as a propellant [syn: smokeless powder, Ballistite]