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 its practical purpose, significant emphasis is also usually given to decorative and aesthetic features.