stereo- Look up stereo- at Dictionary.com
before vowels stere-, word-forming element meaning "solid, firm; three-dimensional; stereophonic," from comb. form of Greek stereos "solid," from PIE *ster- (1) "stiff, rigid, firm, strong" (cognates: Greek steresthai "be deprived of," steira "sterile," sterphnios "stiff, rigid," sterphos "hide, skin;" Latin sterilis "barren, unproductive;" Sanskrit sthirah "hard, firm," starih "a barren cow;" Persian suturg "strong;" Lithuanian storas "thick," stregti "to become frozen;" Old Church Slavonic strublu "strong, hard," sterica "a barren cow," staru "old" (hence Russian stary "old"); Gothic stairo "barren;" Old Norse stirtla "a barren cow," Old English starian "to stare," stearc "stiff, strong, rigid," steorfan "to die," literally "become stiff," styrne "severe, strict").