Prior art is any evidence that your invention is already known. Prior art consists of all information that has been disclosed to the public in any form about an invention and which could call into question an inventor's claims that his or her invention is wholly original. Prior art does not need to exist physically or be commercially available. It is enough that someone, somewhere, sometime previously has described or shown or made something that contains a use of technology that is very similar to your invention. Prior art includes things like any patents related to your invention, any published articles about your invention, and any public demonstrations. Prior art could disqualify your application for a patent, and can be used to contest the validity of a patent.
Examples of Prior Art