Forgery is a commonly, if uncomfortably, recognized force in the art world. It might be assumed, then, that the meaning of the term forgery is uniformly established. That assumption would be a mistake. Although forgery in general parlance has a basic, easily understood meaning, specialists of various stripes employ the term in restricted ways that bear the potential for confusion not only among the cognoscenti but for the broader public. In particular, legal terminology often avoids the term forgery altogether in regard to artworks, and several competing and incompatible versions of the difference between a forgery and a “fake” are in circulation in books, on web-sites, and in the literature of certain professional groups. Differentiating forgeries from fakes makes for an exercise in semantics that, while sometimes offering helpful explications, on the whole bodes difficulty. In our age of increasingly shared information, it is possible to inform members of limited groups, as well as other people taking an interest in their activities, about the specific meaning of forgery that is employed by a group. The result can be a helpful understanding for insiders. However, when restricted meanings are presented as if they are general meanings and they conflict with established language, confusion is imminent, and rectifying it is difficult if even possible.