relating vs similarity

relating

noun
  • The act of relating, or forming or identifying relationships; relation. 

similarity

noun
  • The relation of sharing properties. 

  • A transformation that preserves angles and the ratios of distances 

  • The property of two matrices being similar. 

  • Closeness of appearance to something else. 

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