[ in-suh-ley-ter, ins-yuh- ]

  1. Electricity.

    • a material of such low conductivity that the flow of current through it is negligible.

    • insulating material, often glass or porcelain, in a unit form designed so as to support a charged conductor and electrically isolate it.

  2. a person or thing that insulates.

Origin of insulator

First recorded in 1795–1805; insulate + -or2

Other words from insulator

  • non·in·su·la·tor, noun

Words Nearby insulator Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use insulator in a sentence

  • The sheath surrounding the nerves acts as an electrical insulator, increasing neural speed by 100-fold.

  • It was more than a question of finding the perfect electrical insulator, though that would be handy too.

    Security | Poul William Anderson
  • 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
  • The insulators are of glass, protected by a wooden shield, of the pattern known as the Wade insulator.

  • For the insulation of the wires he recommended gutta-percha, which was then becoming known as an insulator.

  • In 1854 he introduced the pneumatic dispatch into London, and, in 1856, he patented his well-known double-cup insulator.

British Dictionary definitions for insulator


/ (ˈɪnsjʊˌleɪtə) /

  1. 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

Scientific definitions for insulator


[ ĭnsə-lā′tər ]

  1. 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 © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for insulator


A material that does not easily transmit energy, such as electric current (see also 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 Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.