catch fire vs ignite

catch fire

verb
  • To become engulfed in flames, to combust. 

  • To become very popular or widespread; to take off. 

  • To be inspired by passion or zeal. 

ignite

verb
  • to commence burning. 

  • to spark off (something), to trigger 

  • to set fire to (something), to light (something) 

  • To subject to the action of intense heat; to heat strongly; often said of incombustible or infusible substances. 

How often have the words catch fire and ignite occurred in a corpus of books? (source: Google Ngram Viewer )