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 Then, as an insulator, get a long sleeve thermal jersey. John Pana, cleveland, "What’s the best winter clothing for biking in Northeast Ohio’s freezing temperatures?," 28 Dec. 2020 With its low density, air is an ideal insulator, which is why puffy coats work so well. Ac Shilton, Outside Online, "Want to Get Outside All Winter? Bring Your Thermos.," 29 Nov. 2020 Applying an electric field transformed the stack from a conductor to an insulator and then, suddenly, into a superconductor: a material that frictionlessly conducts electricity. Charlie Wood, Science | AAAS, "Twisted graphene could power a new generation of superconducting electronics," 19 Nov. 2020 Rayhan explained that the power line has an insulator hanging from it, which has a fiberglass rod inside. Washington Post, "Those curious rods hanging from a Dulles Toll Road power line serve a purpose," 31 Oct. 2020 Because body fat is more of an insulator than muscle, people with more fat just beneath the skin should have greater cold tolerance than skinny people. Ned Rozell, Anchorage Daily News, "Why is cold tolerance so unique to each individual?," 11 Oct. 2020 The general idea is that the light pulses redistribute electrons among the energy bands in a way that tips the balance between one phase of the system and another — between a metal and an insulator, say. Quanta Magazine, "Alchemy Arrives in a Burst of Light," 30 Sep. 2020 For more complex devices, Ershad's team used two additional inks: one served as a semiconductor, and the other acted as a dielectric (a type of insulator). Scott Hershberger, Scientific American, "New Pen-and-Ink Method Draws Health Sensors Directly on Skin," 18 Aug. 2020 Snow acts as an insulator, keeping the temperature of the ground under the snow warmer than the air. Dan Nosowitz, Better Homes & Gardens, "The Secret to Planting a Gorgeous Garden Is Knowing Your Hardiness Zone," 20 May 2020

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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Time Traveler for insulator

Time Traveler

The first known use of insulator was in 1801

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Last Updated

16 Jan 2021

Cite this Entry

“Insulator.” Dictionary, Merriam-Webster, Accessed 16 Jan. 2021.

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How to pronounce insulator (audio)

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

Nglish: Translation of insulator for Spanish Speakers

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

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