The Collaborative International Dictionary of English v.0.48:

lampshade \lampshade\, lamp shade \lamp shade\n.
   a protective ornamental covering used to screen the light
   bulb in a lamp from direct view.
   [WordNet 1.5] lampshell

WordNet (r) 3.0 (2006):

lampshade
    n 1: a protective ornamental shade used to screen a light bulb
         from direct view [syn: lampshade, lamp shade]