reexamination proceeding

In United States patent law, a reexamination is a process whereby a third party or inventor can have a patent reexamined by a patent examiner to verify that the subject matter it claims is patentable. In order to have a patent reexamined, the party of interest must submit prior art that raises a "substantial new question of patentability".
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at any time during the enforceability of a patent any person may file a request for the USPTO to conduct a second examination of any claim  of the patent on the basis of prior art patents or printed publications which that person states to be pertinent and applicable to the patent and believes to have a bearing on the patentability (see 37 CFR 1.501). In order for the request for reexamination to be granted, a substantial new question of patentability must be present with regard to at least one patent claim. The request must be in writing and must be accompanied by payment of a reexamination request filing fee as set forth in 37 CFR 1.20(c).

-- see 37 U.S.C. 302, MPEP 2209, et seq., for more

Context: Patent