propellant
n. C1 Advanced US //pɹəˈpɛɫənt// UK //pɹəpˈɛlənt// pro·pel·lant
n. a substance that causes something to move or explode. You usually see this word when talking about things like rockets, guns, or fire extinguishers.
n. a substance that provides the force necessary to move an object or cause an explosion. Often refers to the chemical mixture used in firearms or the gas used to propel a rocket.
The rocket uses liquid hydrogen as a propellant.
The technician checked the propellant levels in the fire extinguisher before the flight took off.
Modern aerospace engineering focuses on developing more efficient propellants that provide greater thrust while minimizing the environmental impact of combustion byproducts.
From propel + -ant.