1) It conceals a light bulb 2) It fits over a light bulb 3) Lamp shade 4) Light fixture 5) Shade 
A lampshade is a fixture that covers the lightbulb on a lamp to diffuse the light it emits. Conical, cylindrical and other forms on floor-, desk- or table top-mounted as well as suspended lamp models are the most common and are made in a wide range of materials. The term can also apply to the glass hung under many designs of ceiling lamp. Beyond i...
[n] - a protective ornamental shade used to screen a light bulb from direct view
lamp shade noun a protective ornamental shade used to screen a light bulb from direct view