deflection vs digression

deflection

noun
  • The act of deflecting or something deflected. 

  • The deviation of a needle or other indicator from its previous position. 

digression

noun
  • An elongation, a deflection or deviation from a mean position or expected path. 

  • An aside, an act of straying from the main subject in speech or writing. 

  • The act of straying from the main subject in speech or writing, (rhetoric) particularly for rhetorical effect. 

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