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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
1795-1805; insulate + -or2
Related forms
noninsulator, noun Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for insulator
  • The dipped-fabric layers act as the conductors while the undipped fabric forms the insulator.
  • It's also, among other things, an extremely good acoustic insulator and virtually transparent.
  • It has a poor blood supply, which makes it an excellent insulator.
  • Operating on the principle of thermodynamics, the hay acts as an insulator and the retained heat slowly cooks the food.
  • Distilled water actually is a fairly good insulator.
  • The windshield isn't growing thicker or or becoming a better insulator.
  • Generally, this is a job for a professional insulator.
  • Further, its a good heat insulator not because of its temperature.
  • It's cool in the summer, and in the winter it acts as an insulator through the trapped air.
  • Snow banked over the covered laid down branches worked as a temperature changing insulator also.
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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