noun (n)

• the act of indicating or pointing out by name(noun.communication)

  Synonym:
  indication
  

  source: wordnet30
• the most direct or specific meaning of a word or expression; the class of objects that an expression refers to(noun.cognition)

  Synonym:
  extension, reference
  

  source: wordnet30
• The marking off or separation of anything.(noun)

  source: webster1913