Original prints are not "copies" of anything, any more than a printed book is a "copy" of the plates from which it is made. To make an original print, the artist creates an image on a plate which is then inked and run by hand through a press. The artist chooses the impressions that meet his standards, and he signs and numbers them, indicating the size of the edition, typically around 150 impressions or so. Each impression is an original print.
At first remove from this process are large-edition prints, numbering in the hundreds or even thousands and printed on high-speed presses. Rather than signing each impression, the artist puts his signature directly into the plate from which the print is made. Such prints can still be correctly classified as "original," however.