noun (n)

• an event that occurs at a critical time(noun.event)

  Example:
  At such junctures he always had an impulse to leave.
  

  Synonym:
  occasion
  

  source: wordnet30
• a crisis situation or point in time when a critical decision must be made(noun.state)

  Example:
  At that juncture he had no idea what to do.
  

  Synonym:
  critical point, crossroads
  

  source: wordnet30
• the shape or manner in which things come together and a connection is made(noun.shape)

  Synonym:
  articulation, join, joint, junction
  

  source: wordnet30
• A joining; a union; an alliance.(noun)

  source: webster1913