in·​su·​la·​tor | \ ˈin(t)-sə-ˌlā-tər How to pronounce insulator (audio) \

Definition of insulator

: one that insulates: such as
a : a material that is a poor conductor (as of electricity or heat) — compare semiconductor
b : a device made of an electrical insulating material and used for separating or supporting conductors

Examples of insulator in a Sentence

Metal is not a good insulator.

Recent Examples on the Web

These insulators accumulate a static charge when rubbed together. Alex Fox, Science | AAAS, "The secret of static electricity? It’s shocking," 12 Sep. 2019 The team used graphene and three other materials to create a four-layer insulator that's about 10 atoms thick. Courtney Linder, Popular Mechanics, "This Science Hack Could Prevent Your Phone from Overheating," 22 Aug. 2019 General admission costs $3, with early birds allowed at 8 a.m. for $15 to browse more than 60 dealer tables offering antique bottles, postcards, stoneware, glassware, fruit jars, insulators, advertising, and other collectibles., "North Calendar: What’s happening this week," 5 Sep. 2019 This behavior is akin to a phase transition, the researchers said — like when a metal changes from a conductor to an insulator under certain conditions. Quanta Magazine, "Strange Metal-like Bonds Discovered in Customized Crystals," 3 Sep. 2019 Electrical arching from faulty insulators has sparked several fires in the past, which cause major delays. Erin Baldassari, The Mercury News, "Weekend BART work to add 40 minutes to some East Bay trips, close two lanes of Highway 24," 13 Aug. 2019 On the surface of a topological insulator, electrons flow smoothly, while on the inside, electrons are immobile. Quanta Magazine, "‘Quantum Atmospheres’ May Reveal Secrets of Matter," 25 Sep. 2018 As before, an electric field switched the device into an insulator. David H. Freedman, WIRED, "Physicists Are Bewitched by Twisted Graphene's 'Magic Angle'," 5 May 2019 The team landed on silica aerogel, a 97 percent porous material that allows light through but is an insulator that slows the conduction of heat. Jason Daley, Smithsonian, "This Material May Make Human Habitation on Mars Possible," 18 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'insulator.' 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 insulator

1801, in the meaning defined above

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Last Updated

9 Oct 2019

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The first known use of insulator was in 1801

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English Language Learners Definition of insulator

: a material that allows little or no heat, electricity, or sound to go into or out of something


in·​su·​la·​tor | \ ˈin-sə-ˌlā-tər How to pronounce insulator (audio) \

Kids Definition of insulator

: a material (as rubber or glass) that is a poor conductor of electricity, heat, or sound


in·​su·​la·​tor | \ ˈin(t)-sə-ˌlāt-ər How to pronounce insulator (audio) \

Medical Definition of insulator

: a material that is used to provide insulation also : a device made of such material

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More from Merriam-Webster on insulator

Rhyming Dictionary: Words that rhyme with insulator

Spanish Central: Translation of insulator

Nglish: Translation of insulator for Spanish Speakers

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

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