pro·pel·lant /-ˈpɛlənt/
  使推進之物,發射火藥,推進燃料
  propellant
       adj : tending to or capable of propelling; "propellant fuel for
             submarines"; "the faster a jet plane goes the greater
             its propulsive efficiency"; "universities...the seats
             of propulsive thought" [syn: propellent, propelling,
              propulsive]
       n : something that propels [syn: propellent]