Source : Webster's Revised Unabridged Dictionary (1913)

Organizer \Or"gan*i`zer\, n.
   One who organizes.

Source : WordNet®

organizer
     n 1: a person who brings order and organization to an enterprise
          [syn: {organiser}, {arranger}]
     2: someone who enlists workers to join a union [syn: {organiser},
         {labor organizer}]
     3: 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. [syn: {personal digital assistant},
         {PDA}, {personal organizer}, {personal organiser}, {organiser}]