noun (n)

• the act of inspecting or verifying(noun.act)

  Synonym:
  check, check-out procedure
  

  source: wordnet30
• the latest time for vacating a hotel room(noun.time)

  Example:
  The checkout here is 12 noon.
  

  Synonym:
  checkout time
  

  source: wordnet30
• a counter in a supermarket where you pay for your purchases(noun.artifact)

  Synonym:
  checkout counter
  

  source: wordnet30