ignition ignition /ˌɪgˈnɪʃən/

noun

1. The act of setting something on fire  ( firing , ignition , inflammation , kindling , lighting )
   the act of setting something on fire
   
   
2. The mechanism that ignites the fuel in an internal-combustion engine  ( ignition , ignition system )
   the mechanism that ignites the fuel in an internal-combustion engine
    Insert the key into the ignition and turn it to start the engine
   Insert the key into the ignition and turn it to start the engine
   
3. The process of initiating combustion or catching fire  ( ignition )
   the process of initiating combustion or catching fire