noun (n)

• a person who brings order and organization to an enterprise(noun.person)

  Example:
  She was the organizer of the meeting.
  

  Synonym:
  arranger, organiser
  

  source: wordnet30
• someone who enlists workers to join a union(noun.person)

  Synonym:
  labor organizer, organiser
  

  source: wordnet30
• a lightweight consumer electronic device that looks like a hand-held computer but instead performs specific tasks; can serve as a diary or a personal database or a telephone or an alarm clock etc.(noun.artifact)

  Synonym:
  organiser, pda, personal digital assistant, personal organiser, personal organizer
  

  source: wordnet30
• One who organizes.(noun)

  source: webster1913