noun (n)

• a happening that is distinctive in a series of related events(noun.event)

  source: wordnet30
• a brief section of a literary or dramatic work that forms part of a connected series(noun.communication)

  source: wordnet30
• a part of a broadcast serial(noun.communication)

  Synonym:
  installment, instalment
  

  source: wordnet30
• film consisting of a succession of related shots that develop a given subject in a movie(noun.artifact)

  Synonym:
  sequence
  

  source: wordnet30
• A separate incident, story, or action, introduced for the purpose of giving a greater variety to the events related; an incidental narrative, or digression, separable from the main subject, but naturally arising from it.(noun)

  source: webster1913