A substance that is used to propel something, especially a rocket or missile. The engineers tested a new type of propellant to increase the rocket's efficiency.
A gas or liquid under pressure in a container, used to expel the contents when the pressure is released. The spray can uses a propellant to release the paint evenly.
An explosive charge that propels a projectile from a firearm. Smokeless powder is the standard propellant in modern rifle cartridges.