fi·ber·glass | \ ˈfī-bər-ˌglas \

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

Boards made from fiberglass, wood veneer, or a plastic outer skin are often more durable but heavier. Dylan Silver, Outside Online, "The Best Stand-Up Paddleboards of 2018," 5 July 2018 Photographer: SeongJoon Cho/Bloomberg Workers apply layers of fiberglass to a hull at Winnebago Industries Inc.'s Chris-Craft boat-manufacturing facility in Sarasota, Florida, on June 19., "Bloomberg’s Week in Pictures," 21 June 2018 The new balcony doors will be made of fiberglass specially made by a Maryland company and include glass transoms above the doors and fiberglass door frames. Washington Post, "Zinke says Interior negotiating lower price for $139K doors," 15 Mar. 2018 For comparison, the aluminum and fiberglass Lockheed Lounge by Mark Newsom set an auction record for a living designer when it was sold for $3.7 million in 2015. Patrick Sisson, Curbed, "Rare Noguchi marble table expected to fetch $1M at auction," 22 Mar. 2018 The most popular screen repair kits are now adhesive and can be used on fiberglass or metal screens. Timothy Dahl, Popular Mechanics, "How to Repair a Torn Window Screen," 2 Apr. 2018 The panel has been repaired with Bondo, fiberglass or some other nonmetallic dent filler 2. Indianapolis Star, "How to Inspect a Used Car," 22 Mar. 2018 The price tag on working gillnetters can be as low as ten grand for an out-of-repair fiberglass Rawson or as much as $400,000 for a fancy new aluminum drift boat with full refrigeration. John Schandelmeier, Anchorage Daily News, "At Bristol Bay, there’s a changing of the guard at the boatyard," 7 July 2018 The walk-in shower is easy-to-maintain acrylic fiberglass. Tony Bacewicz,, "West River Farms, East Windsor," 28 June 2018

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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Last Updated

20 Sep 2018

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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 \

Kids Definition of fiberglass

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

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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).


occurring twice a year or every two years

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