einstein vs pixie

einstein

noun
  • One mole of photons, regardless of frequency, as used to measure irradiance. 

  • A genius; a very smart person. 

  • A shape that can be repeated to cover a plane with a nonrepeating pattern. 

pixie

noun
  • An upper-atmospheric optical phenomenon associated with thunderstorms, a short-lasting pinpoint of light on the surface of convective domes that produces a gnome. 

  • A butterfly of the genus Melanis. 

  • A cute, petite woman with short hair. 

  • A playful sprite or elflike or fairy-like creature. 

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