hey guys this is somethin cool that i learned!  Holo comes from the greek word whole and Gram comes froms the greek word message.  A halogram is a 3D version of a photograph that contains the whole message or entire picture in every portion of its surface.
     Let me brake it down for you!

A hologram is produced by the interference between 2 laser light beams on photographic film. the 2 beams are part of 1 beam. one part illuminates the object and is reflected from the object to the film. the second part called the reference beam, is reflected from a mirror to a film.