Source : Webster's Revised Unabridged Dictionary (1913)

Ignition \Ig*ni"tion\, n. [Cf. F. ignition.]
   1. The act of igniting, kindling, or setting on fire.

   2. The state of being ignited or kindled. --Sir T. Browne.

Source : WordNet®

ignition
     n 1: the process of initiating combustion
     2: the mechanism that ignites the fuel in an
        internal-combustion engine [syn: {ignition system}]
     3: the act of setting on fire or catching fire [syn: {firing},
        {lighting}, {kindling}, {inflammation}]