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[in-suh-ley-ter, ins-yuh-] /ˈɪn səˌleɪ tər, ˈɪns yə-/
  1. a material of such low conductivity that the flow of current through it is negligible.
  2. insulating material, often glass or porcelain, in a unit form designed so as to support a charged conductor and electrically isolate it.
a person or thing that insulates.
Origin of insulator
First recorded in 1795-1805; insulate + -or2
Related forms
noninsulator, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for insulator
Historical Examples
  • No alarm from the insulator had come, yet for myself I had not forgotten that Venus girl outside.

    Tarrano the Conqueror Raymond King Cummings
  • Each one that will not make it ring is a poor conductor or an insulator.

    Common Science Carleton W. Washburne
  • It was not until gutta-percha began to be used as an insulator for submarine lines that any substantial progress was made.

  • It must therefore be considered rather as a partial conductor than as an insulator.

    On Laboratory Arts Richard Threlfall
  • Such results can readily be avoided by cementing each iron pin into its insulator, instead of screwing the insulator onto the pin.

  • The action of its particles differs from those of an insulator only in degree.

  • Its strength and durability make it one of the best western woods for insulator pins for telephone and telegraph lines.

    American Forest Trees Henry H. Gibson
  • Any insulator, such as a hot pad or rope or even sticks, will also work.

    The BYU Solar Cooker/Cooler Steven E. Jones
  • Speaking generally, the conductors are separated by some insulator.

  • Omega explained that likely its bony scales had acted as an insulator against the action of the invisible wall.

    Omega, the Man Lowell Howard Morrow
British Dictionary definitions for insulator


any material or device that insulates, esp a material with a very low electrical conductivity or thermal conductivity or something made of such a material
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for insulator

1801, agent noun in Latin form from insulate.

Online Etymology Dictionary, © 2010 Douglas Harper
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insulator in Science
A material or an object that does not easily allow heat, electricity, light, or sound to pass through it. Air, cloth and rubber are good electrical insulators; feathers and wool make good thermal insulators. Compare conductor.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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insulator in Culture

insulator definition

A material that does not easily transmit energy, such as electric current or heat. Materials such as wood, plastic, and ceramics are insulators. Fiberglass is an example of a heat insulator. (Compare conductor.)

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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