noun (n)

• the process of initiating combustion or catching fire(noun.process)

  source: wordnet30
• the mechanism that ignites the fuel in an internal-combustion engine(noun.artifact)

  Synonym:
  ignition system
  

  source: wordnet30
• the act of setting something on fire(noun.act)

  Synonym:
  firing, inflammation, kindling, lighting
  

  source: wordnet30
• The act of igniting, kindling, or setting on fire.(noun)

  source: webster1913