fi·​ber·​glass | \ ˈfī-bər-ˌglas How to pronounce fiberglass (audio) \

Definition of fiberglass

 (Entry 1 of 2)

1 : glass in fibrous form used in making various products (such as glass wool for insulation)
2 : a composite structural material of plastic and fiberglass


fiberglassed; fiberglassing; fiberglasses

Definition of fiberglass (Entry 2 of 2)

transitive verb

: to protect or repair by applying fiberglass

Examples of fiberglass in a Sentence

Recent Examples on the Web: Noun

Each blade weighs 19,600 pounds and is made of fiberglass, plastic, carbon and other composite materials., "Largest wind turbine blade shipment unloads in Vancouver," 26 June 2019 This Scout has a 60-pound factory hardtop that is made of fiberglass and takes at least two people to install or remove. David Krumboltz, The Mercury News, "Me & My Car: Lafayette owner’s ’67 Scout ‘a mobile man-cave’," 10 June 2019 Layered fiberglass and resin, G10 has emerged as a favorite. Chuck Thompson, Popular Mechanics, "Why Portland, Oregon, is the Knife-making Capital of the U.S.," 25 May 2019 From fiberglass, to porcelain, to ceramic, most types of tubs can be upgraded. Kelly Dawson, House Beautiful, "How to Paint a Bathtub," 26 Apr. 2019 The giant eyeball is largely the work of welding students at Richland Community College, who built a metal frame, then added 4,000 small squares of Styrofoam, two layers of fiberglass and six coats of paint. USA TODAY, "Moon rocks, Misty of Chincoteague, Haiku Stairs: News from around our 50 states," 28 June 2019 Up to 50 classic wood, fiberglass and aluminum boats will be shown 10 a.m. to 4 p.m. at the waterfront at the White Bear shopping center located at White Bear Avenue and U.S. 61. Molly Korzenowski, Twin Cities, "White Bear Lake Classic and Vintage Boat show to include iconic ‘Queen Mary’," 21 June 2019 The industry standard is rock wool, a material very similar to fiberglass that is extremely porous and holds 16 times its weight in water. Daniel Kluko, Popular Mechanics, "How to Grow Hydroponic Plants at Home," 13 Feb. 2017 Families loved them for hot dogs, hamburgers, pastrami sandwiches and chili — and the giant fiberglass dachshund heads that stood outside each restaurant. Janelle Bitker,, "Bay Area man wants to resurrect the famed Doggie Diner," 5 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fiberglass.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fiberglass


1937, in the meaning defined at sense 1


1967, in the meaning defined above

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Statistics for fiberglass

Last Updated

9 Aug 2019

Look-up Popularity

Time Traveler for fiberglass

The first known use of fiberglass was in 1937

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More Definitions for fiberglass



English Language Learners Definition of fiberglass

: a light and strong material that is made from thin threads of glass and that is used in making various products


fi·​ber·​glass | \ ˈfī-bər-ˌglas How to pronounce fiberglass (audio) \

Kids Definition of fiberglass

: glass in the form of fibers used in various products (as filters and insulation)

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More from Merriam-Webster on fiberglass

Rhyming Dictionary: Words that rhyme with fiberglass

Spanish Central: Translation of fiberglass

Nglish: Translation of fiberglass for Spanish Speakers Encyclopedia article about fiberglass

Comments on fiberglass

What made you want to look up fiberglass? Please tell us where you read or heard it (including the quote, if possible).


a usually brief trip or an expedition

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