But it is a quite accurate definition of the word fiberglass. It does not cover the many different things people may mean when they say fiberglass, though. If the definition we are using most often didn't concern polymers somehow, we wouldn't even be thinking about fiberglass, right?
So the working definition of fiberglass that these pages will use refers to a fiberglass composite rather than simply the fiberglass threads. In instances where this text refers to fiberglass thread by itself, it will be denoted or reffered to as 'cloth' or 'fiber'.