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polystyrene vs. Styrofoam

polystyrene

[pol-ee-stahy-reen, -steer-een] / ˌpɒl iˈstaɪ rin, -ˈstɪər in /

noun

Chemistry.

a clear plastic or stiff foam, a polymer of styrene, used chiefly as an insulator in refrigerators and air conditioners.

Styrofoam

[stahy-ruh-fohm] / ˈstaɪ rəˌfoʊm /

Trademark.