digression vs diversion

digression

noun
  • 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. 

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

diversion

noun
  • A tactic used to draw attention away from the real threat or action. 

  • A hobby; an activity that distracts the mind. 

  • A detour, such as during road construction. 

  • Officially halting or suspending a formal criminal or juvenile justice proceeding and referral of the accused person to a treatment or care program. 

  • The act of diverting. 

  • Removal of water via a canal. 

  • The rerouting of cargo or passengers to a new transshipment point or destination, or to a different mode of transportation before arrival at the ultimate destination. 

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