noun (n)

• the opening of a subject to widespread discussion and debate(noun.communication)

  Synonym:
  dissemination, public exposure, spreading
  

  source: wordnet30
• a short excursion (a walk or ride) in the open air(noun.act)

  Example:
  He took the dogs for an airing.
  

  source: wordnet30
• the act of supplying fresh air and getting rid of foul air(noun.act)

  Synonym:
  ventilation
  

  source: wordnet30
• A walk or a ride in the open air; a short excursion for health's sake.(noun)

  source: webster1913