episode vs perdurant

episode

noun
  • An incident, action, or time period standing out by itself, but more or less connected with a complete series of events. 

  • An instalment of a drama told in parts, as in a TV series. 

perdurant

noun
  • A happening; an entity that only exists partially at any given point in time. 

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