in·​su·​la·​tor ˈin(t)-sə-ˌlā-tər How to pronounce insulator (audio)
: one that insulates: such as
: a material that is a poor conductor (as of electricity or heat) compare semiconductor
: 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 Materials like von Klitzing’s super-chilled samples are now referred to as topological insulators, because even though their interiors are insulators, topology allows current to flow around their edges. Katie McCormick, Quanta Magazine, 18 July 2023 The retracted paper does not involve superconductivity but rather describes how a relatively mundane material, manganese sulfide, shifts its behavior from an insulator to a metal and then back to an insulator under increasing pressure. Kenneth Chang, New York Times, 26 July 2023 Since plastic is an insulator, static electricity can build up. Tim Johnson, Chicago Tribune, 25 June 2023 Lisa Battiston, a T spokesperson, said that a third rail insulator had overheated. Travis Andersen and,, 28 June 2023 Because the lunar soil acts as a good insulator, dampening the temperature variations between day and night, the microwave emissions largely reflect the flow of heat from the moon’s interior. Kenneth Chang, New York Times, 12 July 2023 Along with these wires, transmission towers also have large porcelain or ceramic disk insulators to connect the conducting wires to the tower. Darren Orf, Popular Mechanics, 8 June 2023 The materials are fabricated using ordinary metals and electrical insulators, or dielectrics. IEEE Spectrum, 3 Sep. 2022 Four height-adjustable insulator legs—with special damping rubber—further eliminate feedback and external vibration. Robert Ross, Robb Report, 7 June 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'insulator.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1801, in the meaning defined above

Time Traveler
The first known use of insulator was in 1801

Dictionary Entries Near insulator

Cite this Entry

“Insulator.” Dictionary, Merriam-Webster, Accessed 25 Sep. 2023.

Kids Definition


in·​su·​la·​tor ˈin(t)-sə-ˌlāt-ər How to pronounce insulator (audio)
: one that insulates
especially : a material that is a poor conductor of heat or electricity or a device made of such material

Medical Definition


in·​su·​la·​tor ˈin(t)-sə-ˌlāt-ər How to pronounce insulator (audio)
: a material that is used to provide insulation
also : a device made of such material

More from Merriam-Webster on insulator

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