発泡スチロール 発泡ポリスチレン
A material made of polystyrene with many embedded air pockets. It is lightweight and has good thermal insulation.

It is often used in packaging material (e.g. [[egg carton]]s, [[tray]]s used in [[food packaging]], [[take-out]] food containers; as a filler for shipping (such as as [[packing peanuts]]); or as a type of [[disposable cup]] for hot beverages (especially [[disposable coffee cup|coffee cup]]s).
styrofoam