polystyrene
/ˌpɑliˈstaɪrin/
noun
- A light, white plastic material used for packaging, insulation, and making disposable cups and containers.
- The takeout container was made of polystyrene and kept the food warm.
- We used sheets of polystyrene to insulate the attic.
- Many coffee shops have stopped using polystyrene cups because they are bad for the environment.