Home › Words › S › styrofoamstyrofoam/ˈstaɪ.ɹə.fəʊm/styrofoam means expanded polystyrene foam, such as is used in cups and packaging.Among words judged in Lexicurio's Arena, styrofoam ranks #16,733 of 42,747 for Qualifying.styrofoam is pronounced /ˈstaɪ.ɹə.fəʊm/.EtymologyGenericized trademark of Styrofoam, from -styr- (from polystyrene) + -o- + foam.nounExpanded polystyrene foam, such as is used in cups and packaging.e.g.“A while ago I read your column concerning the effects of hot tea on styrofoam cups.” — 1988 November 4, Cecil Adams, “The Straight Dope”, in Chicago Reader:Definitions & examples from Wiktionary (CC BY-SA 3.0).