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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. 2018.
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Examples from the Web for insulator
Historical Examples
  • Each one that will not make it ring is a poor conductor or an insulator.

    Common Science Carleton W. Washburne
  • It must therefore be considered rather as a partial conductor than as an insulator.

    On Laboratory Arts Richard Threlfall
  • The action of its particles differs from those of an insulator only in degree.

  • The wood is used for posts, cross-ties, wagon hubs, and insulator pins.

    Studies of Trees Jacob Joshua Levison
  • Speaking generally, the conductors are separated by some insulator.

  • This forms an insulator which is not affected by heat or moisture.

  • Any insulator, such as a hot pad or rope or even sticks, will also work.

    The BYU Solar Cooker/Cooler Steven E. Jones
  • 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
  • Electricity or electrons flow (easier) (harder) (about the same) in a conductor than in an insulator.

  • A wire was led through an insulator, so that the stream of electricity could be subjected to experiment in the Hut.

    The Home of the Blizzard Douglas Mawson
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 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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