In general, philatelic fakes and forgeries refers to labels that look like postage stamps but are not. Most have been produced to deceive or defraud. Learning to identify these can be a challenging branch of philately.
To a large extent the definitions below are consistent with those given in the introduction to various recent editions of the Scott Standard Postage Stamp Catalogue. "We use the term "forgery" to indicate stamps produced to defraud collectors (properly known as forgeries) and to defraud stamp-issuing governments (properly known as counterfeits). "Fake" is used to indicate the alteration of a genuine stamp to make it appear as something else. Fakes might refer to cancellations, overprints, added or clipped perforations, stamp design alterations, etc." Although some philatelists stick to precise definitions of these terms, one should not assume that this is the case with every writer.
Questions are often raised about when a stamp is legitimately produced for postage. The following quotation may be helpful:
The first postage stamp was issued in Great Britain in 1840, and by the early 1860s or earlier the first postage stamp forgery - in the sense of a stamp created to fool philatelists into thinking that it is a genuine one - appeared on the market. By 1863 forgeries were so common that the book Forged Stamps: How to Detect Them was published and by 1864, forgeries were being produced of both common and scarce stamps from a wide range of issuing countries such as Austria, British Guiana, Finland, India and Spain.
Jean de Sperati is among the master forgers in the history of philately. The Vancouver Island forgery refers to a stamp that was originally issued in 1865. To produce his forgery, de Sperati bleached a real, cheaper stamp of the same vintage. He then used a process called photolithography to make an almost perfect copy of the stamp. In his lifetime, Jean de Sperati forged over 500 stamps. He sometimes signed his work in pencil on the back. His forged stamps are now often worth more than the originals.
Stamp-like objects, not all of which are really fakes and forgeries, are described below for the sake of developing a better understanding of such claims.
Those who produce counterfeits appeal to a very different market from philatelists. They depend on their stamps being produced in large quantities in order to be able to recover their outlay. The person who would use them must feel that he can purchase them for a price that is significantly lower than what he would pay at a legitimate post office. This makes the most common current stamp used for everyday mailing a prime target for counterfeiting activity.