A print is called a reproduction if it has been made by someone other than the original artist of the conceptual design. A reproductive print often passes through a series of reproductive processes such as a lithographic print of a photograph of an oil painting. Nowadays some artists are a willing party to putting out a limited edition of such a sequence, which are also duly signed and numbered. The rules concerning "originals" and "reproductions" are often bent and expanded, so it is definitely a case of caveat emptor. The best way to distinguish between "originals" and "reproductions" is to arm yourself with knowledge and experience.