episodic vs parenthetical

episodic

adj
  • sporadic, happening infrequently and irregularly 

  • made up a sequence of seemingly unconnected episodes 

  • relating to an episode 

parenthetical

adj
  • that is incidental 

  • that explains or qualifies something 

  • using, containing, or within parenthesis 

noun
  • A word or phrase within parentheses. 

  • A descriptor or modifier enclosed within parentheses and put, indented, in a line of dialogue to describe how it should be acted or directed onscreen. 

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