Definition of "organizer"

A person who arranges the details of a public event.  examples

(computing) A hand-held micro-computer that will perform specific tasks; can be used as an electronic diary, alarm clock, recorder of memos and notes, a portable database etc.  examples

A non-electronic notebook or calendar or something similar, used to organize one's affairs.  examples

(medicine) A group of cells that, together with the evocator, control differentiation in the embryo; the inductor  examples