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

Definition of glass

 (Entry 1 of 4)

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 4)

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)


biographical name (1)
\ ˈglas How to pronounce Glass (audio) \

Definition of Glass (Entry 3 of 4)

Carter 1858–1946 American statesman


biographical name (2)

Definition of Glass (Entry 4 of 4)

Philip 1937–     American composer

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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.
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Recent Examples on the Web: Noun The house has walls of glass and an open floor plan. Nancy Keates, WSJ, "In California, a Former Journalist Discovers a New Beat: Architecture," 28 Apr. 2021 Maddon has gone against the conventional wisdom of the time, which is to handle talented players as if they’re made of glass, and removed the usage restrictions designed to keep Ohtani healthy. Los Angeles Times, "Column: Shohei Ohtani’s Ruthian two-way journey began in Japan, accelerated under Joe Maddon," 27 Apr. 2021 The Sun does not have to be made of glass to act like a lens. Chron, "Astronomers propose using the Sun to send messages to other stars," 26 Apr. 2021 The custom doors feature linen between panes of glass and have frames and handles in wenge. Alexandra Lange, ELLE Decor, "Does This Roman Penthouse Have the World’s Best View? See for Yourself," 22 Apr. 2021 Tailored for enjoying the scenery that surrounds it, the house features arched expanses of glass framed in brick that bring spectacular views into the main living area. Neal Leitereg, Forbes, "What $3.4 Million Buys In Real Estate In France, Mexico And Spain," 21 Apr. 2021 The new design is incredible, with a razer-thin housing and a single sheet of glass that covers the entire front of the display. Zach Epstein, BGR, "8 big announcements from the Apple event that fans can’t stop talking about," 20 Apr. 2021 So for now the Twins are left to persevere through the dark times, peering from behind the thin pane of glass separating them from the light. Megan Ryan, Star Tribune, "Monday's Twins game also postponed as team deals with positive COVID-19 tests," 18 Apr. 2021 Its three sides of glass open to the generous grounds and gardens. Judy Rose, Detroit Free Press, "$2.3M Tudor in Ann Arbor combines its past with big modern improvements," 17 Apr. 2021 Recent Examples on the Web: Verb The plan was simple: Walk out to points of long ridges and glass open areas below. Jace Bauserman, Outdoor Life, "Worth the Wait: It Took 10 Years, but a Mother-Daughter Team Finally Killed Two Massive Colorado Mule Deer," 23 Dec. 2020 Years ago, the industry switched from metal backs to glass in order to facilitate wireless charging, since the RF signals couldn't penetrate metal. Ron Amadeo, Ars Technica, "Pixel 5 teardown shows off the guts of Google’s latest flagship," 2 Nov. 2020 There, several glassed-in enclosures contained multiple cubs, the couple says. Matt Wake |, al, "‘Tiger King’: Alabama ties to bonkers Netflix hit," 17 Apr. 2020 Throughout the night, Wolf zipped between the gleaming glassed-in kitchen and the dining room, touching both the tables of regulars and strangers like me. Adam Erace, Fortune, "Charleston Restaurant is the most relaxed formal dining experience in Baltimore," 8 Mar. 2020 Fit hunters glassing the Salmon River’s breaks in spring can find multiple bears on any given evening. Andrew Mckean, Outdoor Life, "The Best Black Bear Hunting Unit in the Word," 2 Apr. 2020 But some of the small glassed-in study rooms have at least four students grouped around the table, putting them much closer than six feet from each other. Alec Macgillis, ProPublica, "What’s It Like on One of the Only University Campuses Still Open in the U.S.?," 26 Mar. 2020 Colglazier was glassing when dawn broke on the Kansas rifle season. Scott Bestul, Field & Stream, "The Best Bucks of December 2019," 7 Jan. 2020 Carson’s glassed-in kitchen, perched above the entrance, overlooks the whole scene like a command center. Los Angeles Times, "Review: At Bon Temps in Downtown L.A., the brilliant desserts are only the beginning," 29 Aug. 2019

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.

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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

Time Traveler

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

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Statistics for glass

Last Updated

1 May 2021

Cite this Entry

“Glass.” Dictionary, Merriam-Webster, Accessed 7 May. 2021.

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More Definitions for glass



English Language Learners Definition of glass

 (Entry 1 of 2)

: a hard usually transparent material that is used for making windows and other products
: a drinking container made out of glass
: the amount held by a glass container



English Language Learners Definition of glass (Entry 2 of 2)

: to fit, protect, or enclose (something) with 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

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