Loosely, all information that is publicly available before someone claims to invent something. Patents are only allowed for things that are novel and nonobvious. If the prior art contained a description of the supposed invention, it usually cannot be novel. If the prior art contained enough information that the invention would have been obvious to someone of ordinary skill in the relevant field, a patent also cannot issue. See 35 U.S.C. §§ 102(a), 103(a).
Definition from Nolo’s Plain-English Law Dictionary
In patent law, all technology and publications available before the date of invention or anything available about the invention more than one year prior to filing the application. A patent will not issue if prior art is uncovered by a patent examiner that demonstrates somebody already came up with the same idea -- that is, all of the significant elements in the applicant's innovation were embodied in an existing innovation.
Definition provided by Nolo’s Plain-English Law Dictionary.
August 19, 2010, 5:22 pm