A regular production cel was used in the
production of the anime. It's an unique.

A limitied edition cel was produced for fans after
the production of the anime.
It was not used in the production of the anime and
is mostly produced in a limited number.
There are limited edition cels which are
handpainted and ones wich are printed.

I made a list of different cel types with example
pictures. Text is in german, but I think it can
help you a bit, too.
http://cels.de/CelHP/cel_begriffe.htm