noun (n)

• the act of continuing an activity without interruption(noun.act)

  Synonym:
  continuation
  Antonym:
  discontinuance, discontinuation
  

  source: wordnet30
• the period of time during which something continues(noun.time)

  Synonym:
  duration
  

  source: wordnet30
• the property of enduring or continuing in time(noun.time)

  source: wordnet30
• A holding on, or remaining in a particular state; permanence, as of condition, habits, abode, etc.; perseverance; constancy; duration; stay.(noun)

  source: webster1913