semblance vs similarity

semblance

noun
  • the way something looks; appearance; form 

  • likeness, similarity; the quality of being similar. 

similarity

noun
  • Closeness of appearance to something else. 

  • A transformation that preserves angles and the ratios of distances 

  • The property of two matrices being similar. 

  • The relation of sharing properties. 

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