insulator

American  

[in-suh-lay-ter, ins-yuh-] / ˈɪn səˌleɪ tər, ˈɪns jə- /

noun

• insulators
  plural

1. Electricity.

   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.

2. a person or thing that insulates.

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insulator British  

/ ˈɪnsjʊˌleɪtə /

noun

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

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insulator Scientific  

/ ĭn′sə-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.

2. Compare conductor

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insulator Cultural  

1. 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.)

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Other Word Forms

Derived Forms

• noninsulator
  noun

Inflected Forms

Nouns

• insulators
  plural

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Etymology

Origin of insulator

First recorded in 1795–1805; insulate + -or ²

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Explanation

Any material that keeps energy such as electricity, heat, or cold from easily transferring through is an insulator. Wood, plastic, rubber, and glass are good insulators. Swiss cheese...not so much. The word insulator comes from the Latin root insulātus, which means "like an island." If your house is built out of good insulators, you might enjoy an island of warmth inside it even during cold winter nights. The opposite of insulator is conductor: a material that easily transmits heat or electricity.

Example Sentences

See Examples For:

insulator insulators

The inquest heard the company had since brought in changes, stopped using that type of insulator and was rolling out a programme to replace them at about 8,000 locations.

From BBC ● Jan. 29, 2026

A typical double-hung window—even a double-glazed one—is so leaky, and such a poor insulator, that if your home were a bucket, your windows are effectively holes in it.

From The Wall Street Journal ● Nov. 21, 2025

"For years, scientists have pursued the answer to a fundamental question about the carrier origin in this exotic insulator: Is it from the bulk or the surface, intrinsic or extrinsic?" said Chen.

From Science Daily ● Nov. 9, 2025

Industry experts have told the BBC spray foam is an effective insulator if fitted properly, and urgent action is needed to stop panicked homeowners needlessly turning to "cowboy" removal companies.

From BBC ● Dec. 4, 2024

Our sleeping-bags, coats, and hoods were lined with that same fur, an unsurpassed insulator and very beautiful to see.

From "The Left Hand of Darkness" by Ursula K. Le Guin

She increased prices this summer between 10% and 21% on all of her products, which include plastic insulators for high-voltage transmission wires.

From The Wall Street Journal ● Sep. 15, 2026

In the experiments overseen by Smoleński and Imamoğlu, the researchers were able to tune the electrons between topological states that behave as insulators and those that conduct electricity like metals.

From Science Daily ● Mar. 3, 2026

The issue had been caused by voids in the cement around the insulators.

From BBC ● Jan. 29, 2026

Germanium and silicon, both group IV elements with diamond-like crystal structures, occupy a unique position between metals and insulators.

From Science Daily ● Oct. 30, 2025

The rest of it was strange to her; she could see no principle behind the coils, the jars, the banks of insulators, the lattice of tubing.

From "The Amber Spyglass" by Philip Pullman

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