existence vs reality

existence

noun
  • The state of being, existing, or occurring; beinghood. 

  • Empirical reality; the substance of the physical universe. (Dictionary of Philosophy; 1968) 

reality

noun
  • The state of being actual or real; realness. 

  • The entirety of all that is real. 

  • The real world. 

  • An individual observer's own subjective perception of that which is real. 

  • A real entity, event, or other fact. 

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