noun (n)

• an occurrence of improvement by virtue of preventing loss or injury or other change(noun.event)

  Synonym:
  preservation
  

  source: wordnet30
• the preservation and careful management of the environment and of natural resources(noun.act)

  source: wordnet30
• (physics) the maintenance of a certain quantities unchanged during chemical reactions or physical transformations(noun.cognition)

  source: wordnet30
• The act of preserving, guarding, or protecting; the keeping (of a thing) in a safe or entire state; preservation.(noun)

  source: webster1913