noun (n)

• a technical system of symbols used to represent special things(noun.communication)

  Synonym:
  notational system
  

  source: wordnet30
• a comment or instruction (usually added)(noun.communication)

  Example:
  He added a short notation to the address on the envelope.
  

  Synonym:
  annotation, note
  

  source: wordnet30
• the activity of representing something by a special system of marks or characters(noun.act)

  source: wordnet30
• The act or practice of recording anything by marks, figures, or characters.(noun)

  source: webster1913