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 These creatures changed so little that an Ohio church set out a 68-foot fiberglass horseshoe crab as testament to divine creation over evolution. Tim Prudente,, "How the coronavirus vaccine relies on Maryland’s strangest fishery: horseshoe crabs," 31 Dec. 2020 Since then, Catalina has built more than 85,000 boats and established itself as the largest U.S.-based maker of fiberglass sailboats. James R. Hagerty, WSJ, "Weekend Sailor Turned a Hobby Into a Big Business," 3 Dec. 2020 And strands of carbon embedded in a thin layer of fiberglass that runs the length of the ski add some smoothness on firmer surfaces. Louis Mazzante, Popular Mechanics, "The Best All-Mountain Skis to Crush It Everywhere," 25 Nov. 2020 Speaking of large gifts, Marie Christianson of Apple Valley, Minnesota, woke up on Christmas morning in 1985 to find an 8-foot tall fiberglass elephant on her front lawn. Dallas News, "Through the ages: Last-minute gift ideas," 13 Dec. 2020 His costume featured a menacing grilled face mask, a glistening black helmet modeled after samurai headgear, a leather jumpsuit, black gloves, knee-high boots, a sweeping cape and a flashing electronic chest panel on a fiberglass breastplate. Louie Estrada, Washington Post, "David Prowse, English actor and weightlifter who embodied Darth Vader, dies at 85," 29 Nov. 2020 The 8-foot Werner fiberglass step ladder is down to $49.97. CNN Underscored, "Black Friday deals on batteries, face masks and more items you’d buy anyway," 26 Nov. 2020 Keen’s Polar Traction outsole, made with fiberglass, works similarly. Adrienne Donica, Popular Mechanics, "Winter is No Match for These Top-Performing Snow Boots," 5 Nov. 2020 The assembly process marries a rigid carbon-composite upper structure and body panels with SPA’s steely underpinnings—a bit like what Lotus used to do with fiberglass. Dan Neil, WSJ, "Polestar 1: The World’s Most Beautiful Hybrid Car Has Arrived," 15 Oct. 2020

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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Time Traveler for fiberglass

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The first known use of fiberglass was in 1937

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Last Updated

15 Jan 2021

Cite this Entry

“Fiberglass.” Dictionary, Merriam-Webster, Accessed 20 Jan. 2021.

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More Definitions for fiberglass


How to pronounce fiberglass (audio)

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)

More from Merriam-Webster on fiberglass

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

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