intensity vs élan

intensity

noun
  • Can mean any of radiant intensity, luminous intensity or irradiance. 

  • Time-averaged energy flux (the ratio of average power to the area through which the power "flows"); irradiance. 

  • Synonym of radiance. 

  • The degree of strength. 

  • The quality of being intense. 

  • The severity of an earthquake in terms of its effects on the earth's surface, and buildings. The value depends on the distance from the epicentre, and is not to be confused with the magnitude. 

élan

noun
  • Spirit; zeal; ardor. 

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