insulator

American  

[in-suh-ley-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

Etymology

Origin of insulator

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

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

It is a better thermal insulator and was previously sold to stabilise failing roofs.

From BBC ● Nov. 17, 2024

“Actually, I had. Anyway, if there’s an insulator in place, I can use these new boxes straightaway. Harry...you’ve got children at school, haven’t you?”

From "The Book of Dust: La Belle Sauvage" by Philip Pullman

This makes it especially valuable for studying insulators or magnetic materials that can interfere with charged particle beams.

From Science Daily ● Apr. 28, 2026

"We are left to speculate some, as our ability to interrogate insulators stops a little," explained Dean -- their expertise is in transport measurements, and insulators don't transport a current.

From Science Daily ● Feb. 5, 2026

As part of ENWL's investigation it tested 260 insulators across its network and found 73% contained voids.

From BBC ● Jan. 29, 2026

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

From BBC ● Jan. 29, 2026

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