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

For decades, asbestos was a popular fire retardant and insulator in buildings, up until the 1970s. —Kenneth R. Gosselin, Hartford Courant, 24 Apr. 2026

Because of their elevated position, raised garden beds freeze more easily than in-ground gardens, where the surrounding soil acts as a natural insulator. —Michelle Mastro, Martha Stewart, 23 Apr. 2026

When paired with insulators, many combinations form an unavoidable microscopic separation that weakens electrical control. —Neetika Walter, Interesting Engineering, 20 Apr. 2026

Authorities said a frozen layer of snow on top of the ice acts as insulator and prevents further freezing of the ice underneath. —Paul Burton, CBS News, 16 Feb. 2026

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