A term used to describe a legal objection to the grant of a patent or trademark filed in the relevant trademark or patent office. In the European Patent Office an opposition can be filed for up to nine months from the issue date of the patent.
The United States Patent and Trademark office introduced a post-grant-review procedure for patents similar to that of the EPO under the America Invents Act. Post-grant review is not limited a review of novelty and obviousness based on prior art, lack of written description, non-enablement, or ineligible subject matter. If post-grant review is initiated after a 2-month period for the patent owner’s response to a petition for review and a 3-month period for USPTO consideration of the petition, the USPTO has 12 months to complete review (which can be extended to 18 months in “exceptional” circumstances).