Dielectric

1. A substance in which an electric field may be maintained with zero or near-zero power dissipation, i.e. , the electrical conductivity is zero or near zero.

Note 1: A dielectric material is an electrical insulator.

Note 2: In a dielectric, electrons are bound to atoms and molecules, hence there are few free electrons.

2. Pertaining to a substance that has a zero or near zero electrical conductivity.

Source: from Federal Standard 1037C

See also: dielectric strength, dielectric constant