Common designation for letters patent, which is a certificate of grant by a government of an exclusive right with respect to an invention for a limited period of time. A United States patent confers the right to exclude others from making, using, or selling the patented subject matter in the United States and its territories. A United States patent covering a process also, under certain conditions, prohibits the unlicensed sale in the United States of articles made by that process anywhere in the world. Portions of those rights deriving naturally from it may be licenced separately, as the rights to sell, to use, to make, to have made, and to lease. Any violation of this right is an infringement.