A trademark used for expanded polystyrene plastic, a light-weight, granular material, usually worked in sheets or blocks, but also available in loose granules. It can be cut with great precision and ease with an electrically heated wire. Styrofoam is an economically attractive medium for use in theater and motion picture stage sets. Styrofoam is often mentioned in print as [lower-case s] styrofoam.Quote: "When companies ship Styrofoam, what do they pack it in?" Steve Wright, contemporary American comedian. Also see aggregate, foam core, and packaging.