A substance or object that does not permit the passage of some form of energy (as heat or electricity). Also figurative.

One who or that which insulates; e.g. a body or substance that entirely or to a great degree prevents the passage of electricity or heat between…

A substance or medium through or across which electric force acts without conduction; a non-conductor; an insulating medium.

The operation of fitting a hole with a bush. Also concrete = bush, n.3 spec. an electrically insulating device.

concrete. Insulating or non-conductive material.

A body or figure having the shape of a sector; hence, a division or part, a unit. A small piece of ebonite forming part of a Bertsch machine.

Any substance or medium which insulates (electrically, thermally, etc.).