or fi·ber glass

[ fahy-ber-glas, -glahs ]
See synonyms for fiberglass on
  1. a material consisting of extremely fine filaments of glass that are combined in yarn and woven into fabrics, used in masses as a thermal and acoustical insulator, or embedded in various resins to make boat hulls, fishing rods, and the like.

verb (used with object)
  1. to cover or form with fiberglass.

verb (used without object)
  1. to use or work with fiberglass.

Origin of fiberglass

An Americanism dating back to 1935–40; fiber + glass

Words Nearby fiberglass Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use fiberglass in a sentence

Scientific definitions for fiberglass


[ bər-glăs′ ]

  1. A material made up of very fine fibers of glass. Fiberglass is resistant to heat and fire and is used to make various products, such as building insulation and boat hulls. Because the fibers in fiberglass are capable of transmitting light around curves, fiberglass is an important component of fiber optics.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.