noun (n)

• the process whereby a person concentrates on some features of the environment to the (relative) exclusion of others(noun.cognition)

  Synonym:
  attention
  Antonym:
  inattention
  

  source: wordnet30
• the act of being present (at a meeting or event etc.)(noun.act)

  Synonym:
  attendance
  Antonym:
  nonattendance
  

  source: wordnet30