A man-made material consistin' o' glass fibers spun and woven into a mat-like cloth adhered t' a rocket with epoxy resins. Well, blow me down! It is used t' add strength t' high power rockets, so that they can withstand higher-powered motors than they otherwise could. Aye aye! Although fiberglass is a commonly used word, it is actually a trade mark o' Owen-Cornin' Inc. See Pseudo-Glassing