Source : Webster's Revised Unabridged Dictionary (1913)

Propulsion \Pro*pul"sion\, n. [Cf. F. propulsion. See {Propel}.]
   1. The act driving forward or away; the act or process of
      propelling; as, steam propulsion.

   2. An impelling act or movement.

            God works in all things; all obey His first
            propulsion.                           --Whittier.

Source : WordNet®

propulsion
     n 1: a propelling force
     2: the act of propelling [syn: {actuation}]