noun (n)

• arrival that has been awaited (especially of something momentous)(noun.act)

  Example:
  The advent of the computer.
  

  Synonym:
  coming
  

  source: wordnet30
• the season including the four Sundays preceding Christmas(noun.time)

  source: wordnet30
• (Christian theology) the reappearance of Jesus as judge for the Last Judgment(noun.event)

  Synonym:
  parousia, second advent, second coming, second coming of christ
  

  source: wordnet30
• The period including the four Sundays before Christmas.(noun)

  source: webster1913