noun (n)

• the property of making no sound(noun.attribute)

  Synonym:
  soundlessness
  

  source: wordnet30
• a state of peace and quiet(noun.feeling)

  Synonym:
  quietude, tranquility, tranquillity
  

  source: wordnet30
• The quality or state of being quiet; freedom from noise, agitation, disturbance, or excitement; stillness; tranquillity; calmness.(noun)

  source: webster1913