1. A type of rocket propulsion in which the propellant is heated electrically; such as, an electric arc that is used to heat hydrogen gas in an arc-jet engine.
2. The propulsion of spacecraft by using an electric arc or other electric heater to bring hydrogen gas or other propellant to the high temperature required for maximum thrust; for example, an arc-jet engine.
3. Vehicular propulsion which involves electrical heating to raise the energy level of the propellant.

In contrast, chemical rockets use the chemical energy of one or more propellants to heat and to accelerate the decomposition products (monopropellants) or combustion products (bipropellants) for thrusting purposes.

In both instances, the high-energy propellant gases are exhausted through a nozzle where they are accelerated to a high velocity, and thrust is produced by reaction.