propellant

Concise Oxford English Dictionary © 2008 Oxford University Press:
propellant/prəˈpelənt/

▶noun

• 1 an inert fluid, liquefied under pressure, in which the active contents of an aerosol are dispersed.

• 2 an explosive that fires bullets from a firearm.

• 3 a substance used as a reagent in a rocket engine to provide thrust.

▶adjective capable of propelling something.

– origin C17: orig. from L. propellent-, propellere ‘drive ahead (of oneself)’, later from propel.