pro·pel·lant also pro·pel·lent 
(prə-pĕlənt)
(prə-pĕlənt)n.
1. Something, such as an explosive charge or a rocket fuel, that propels or provides thrust.
2. A compressed inert gas, such as a fluorocarbon, that acts as a vehicle for discharging the contents of an aerosol container.
adj.
Serving to propel; propelling.