noun (n)

• a piece of work that exploits or builds on earlier work(noun.artifact)

  Example:
  His new software is a follow-up to the programs they started with.
  

  Synonym:
  followup
  

  source: wordnet30
• an activity that continues something that has already begun or that repeats something that has already been done(noun.act)

  source: wordnet30
• a subsequent examination of a patient for the purpose of monitoring earlier treatment(noun.act)

  Synonym:
  followup, reexamination, review
  

  source: wordnet30