noun, often attributive
\ ˈglas How to pronounce glass (audio) , ˈgläs \

Definition of glass

 (Entry 1 of 2)

1 : any of various amorphous materials formed from a melt by cooling to rigidity without crystallization: such as
a : a usually transparent or translucent material consisting typically of a mixture of silicates
b : a material (such as obsidian) produced by fast cooling of magma
2a : something made of glass: such as
(1) : tumbler also : glassware
(2) : mirror
(3) : barometer
(4) : hourglass
b(1) : an optical instrument or device that has one or more lenses and is designed to aid in the viewing of objects not readily seen
(2) : field glasses, binoculars usually used in plural
c glasses plural : a device used to correct defects of vision or to protect the eyes that consists typically of a pair of glass or plastic lenses and the frame by which they are held in place

called also eyeglasses, spectacles

3 : the quantity held by a glass container
5 : crystal meth specifically : a pure form of crystal meth


glassed; glassing; glasses

Definition of glass (Entry 2 of 2)

transitive verb

1a : to provide with glass : glaze sense 1
b : to enclose, case, or wall with glass the sunroom was glassed in
2 : to make glassy
3a : reflect
b : to see mirrored
4 : to look at through an optical instrument (such as a pair of binoculars)

Other Words from glass


glassful \ ˈglas-​ˌfu̇l How to pronounce glass (audio) \ noun
glassless \ ˈglas-​ləs How to pronounce glass (audio) \ adjective

Synonyms for glass

Synonyms: Noun

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Examples of glass in a Sentence

Noun The waiter filled our glasses with water. She drank two glasses of water. She was wearing dark glasses with thick black frames.
Recent Examples on the Web: Noun This glass bodied Joco mug has a colorful silicone lid and a matching thermal sleeve. Sarah Wharton, Good Housekeeping, 19 Sep. 2022 Completed in 1905, the mansion features carved millwork, stone fireplaces and leaded glass windows, as well as a private rocky beach. Cliff Pinckard, cleveland, 19 Sep. 2022 One woman was injured when glass windows broke inside a gymnasium due to high winds. Adam Sabes, Fox News, 18 Sep. 2022 French doors with frosted glass windows access this suite from the balcony that overlooks the great room. James Alexander, Hartford Courant, 17 Sep. 2022 What each will have, however, is a private foyer and elevator entry, floor-to-ceiling glass windows and doors, and 10- to 14-foot-high ceilings. Emma Reynolds, Robb Report, 9 Sep. 2022 Porter Square Books’ Seaport location makes that dream a reality, and offers cozy studying nooks on both floors that sit right in front of massive glass windows., 28 Aug. 2022 But the theater’s front survived, and Thompson said stained-glass windows inside are intact. oregonlive, 22 Aug. 2022 Inside the house, many period features remain, including parquet flooring, leaded-glass windows and a sleeping porch on the second floor. Kathy Orton, Washington Post, 19 Aug. 2022 Recent Examples on the Web: Verb As businesses switch from plastic containers to glass to meet their sustainable packaging goals, competition for bottles is intensifying. Carol Ryan, WSJ, 23 Aug. 2022 In 1825, the Boston Sandwich Glass Company relocated to Cape Cod because the sand lends itself nicely to glass blowing. Lea Lane, Forbes, 6 July 2022 One of his first acts as Colorado athletic director in 2005 was to change the large wooden doors of his office to glass to encourage visitors. Los Angeles Times, 22 Nov. 2021 It can be made in a variety of materials, from masonry and plastic to glass ad metal. Calvin Finch, San Antonio Express-News, 24 Sep. 2021 The northern Italian city of Venice is a world leader in artisan crafts, from mask making to glass blowing. Rebecca Ann Hughes, Forbes, 21 Sep. 2021 Peach & Lily Your roadmap to glass skin begins (and ends) here. Talia Abbas, Glamour, 27 Aug. 2021 All of the homes on the tour have a great room with an island to gather around and glass doors that slide away to an outdoor oasis. oregonlive, 4 Aug. 2021 The plan was simple: Walk out to points of long ridges and glass open areas below. Jace Bauserman, Outdoor Life, 23 Dec. 2020 See More

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

First Known Use of glass


before the 12th century, in the meaning defined at sense 1


14th century, in the meaning defined at transitive sense 1a

History and Etymology for glass


Middle English glas, from Old English glæs; akin to Old English geolu yellow — more at yellow

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Time Traveler for glass

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The first known use of glass was before the 12th century

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Statistics for glass

Last Updated

22 Sep 2022

Cite this Entry

“Glass.” Dictionary, Merriam-Webster, Accessed 1 Oct. 2022.

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More Definitions for glass


\ ˈglas How to pronounce glass (audio) \

Kids Definition of glass

1 : a hard brittle usually transparent substance commonly made from sand heated with chemicals
2 : a drinking container made of glass
3 glasses plural : a pair of glass or plastic lenses held in a frame and used to help a person see clearly or to protect the eyes
4 : the contents of a glass a glass of milk


noun, often attributive
\ ˈglas How to pronounce glass (audio) \

Medical Definition of glass

1a : an amorphous inorganic usually transparent or translucent substance consisting of a mixture of silicates or sometimes borates or phosphates formed by fusion of silica or of oxides of boron or phosphorus with a flux and a stabilizer into a mass that cools to a rigid condition without crystallization
b : a substance resembling glass especially in hardness and transparency organic glasses made from plastics
2a : an optical instrument or device that has one or more lenses and is designed to aid in the viewing of objects not readily seen
b glasses plural : a device used to correct defects of vision or to protect the eyes that consists typically of a pair of glass or plastic lenses and the frame by which they are held in place

called also eyeglasses

Glass biographical name (1)

\ ˈglas How to pronounce Glass (audio) \

Definition of Glass

 (Entry 1 of 2)

Carter 1858–1946 American statesman


biographical name (2)

Definition of Glass (Entry 2 of 2)

Philip 1937–     American composer

More from Merriam-Webster on glass

Nglish: Translation of glass for Spanish Speakers

Britannica English: Translation of glass for Arabic Speakers Encyclopedia article about glass


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