glass fiber

(materials) A glass thread less than a thousandth of an inch (25 micrometers) thick, used loosely or in woven form as an acoustic, electrical, or thermal insulating material and as a reinforcing material in laminated plastics. Also known as fiberglass.

Filaments of glass, formed by pulling or spinning molten glass into random lengths; either gathered in a wool-like mass or formed as continuous thread-like filaments having diameters in the range of 10 to 30 μ m. The wool-like material is processed into many forms of varying densities for use as thermal and acoustical insulation. The continuous-filament type is used for textiles, glass fabrics, and electrical insulation and as reinforcement for other materials.