Polystyrene | Define Polystyrene at Dictionary.com

polystyrene / ˌpɒl iˈstaɪ rin, -ˈstɪər in / Show Spelled [pol-ee-stahy-reen, - steer-een] Show IPA noun Chemistry. a clear plastic or stiff foam, a polymer of styrene, used chiefly as an insulator in ...

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