insulator

noun

in·​su·​la·​tor ˈin(t)-sə-ˌlā-tər 

: one that insulates: such as

a

: a material that is a poor conductor (as of electricity or heat) compare semiconductor

b

: 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

Because snow is a better insulator than ice—this quality is why igloos work so well—flooding and freezing the snow could allow more cold to penetrate to the ice’s underside, creating more ice. —Alec Luhn, Scientific American, 20 May 2025

Earlier antenna arrays that similarly use smaller component cells include dielectric materials like ceramic or glass to act as insulators. —IEEE Spectrum, 21 July 2021

Plus, the light-blocking curtains also serve as an insulator, blocking out the heat in the summer and cold in the winter. —Maggie Horton, People.com, 18 May 2025

Using gas as an insulator for spacecraft could replace traditional, single-use heat shields that burn away or the heat-resistant ceramic tiles that need to be replaced between flights, making spacecraft more fully and rapidly reusable, according to a statement from Texas A&M University. —Samantha Mathewson, Space.com, 11 May 2025

Word History

First Known Use

1801, in the meaning defined above

Rhymes for insulator

• activator
• actuator
• agitator
• alligator
• allocator
• alternator
• animator
• annotator
• applicator
• arbitrator
• aspirator
• aviator

Kids Definition

insulator

noun

in·​su·​la·​tor ˈin(t)-sə-ˌlāt-ər 

: one that insulates

especially : a material that is a poor conductor of heat or electricity or a device made of such material

Medical Definition

insulator

noun

in·​su·​la·​tor ˈin(t)-sə-ˌlāt-ər 

: a material that is used to provide insulation

also : a device made of such material