Opposition proceeding
An opposition proceeding is an administrative process available under the patent and trademark law of many jurisdictions which allows third parties to formally challenge the validity of a pending patent application ("pre-grant opposition"), of a granted patent ("post-grant opposition"), or of a trademark. == Patents == Patent opposition proceedings are administrative mechanisms within the patent law framework that allow third parties to formally challenge the validity of a pending patent application (pre-grant opposition) or a granted patent (post-grant opposition).