A term used here to denote a patent for invention, an exclusive right granted to work new inventions. It is sometimes called "letters patent," from the Latin litterae patentes ("open letters"), meaning that the royal seal was placed at the bottom of the document, making the document a public record open for all to see. The Patent Act still defines "patent" as "letters patent for an invention," being one species of the genus of letters patent, which at various times covered franchises, land grants, honours, and company incorporations.
A patent lasts for twenty years from the date when the application for it is filed, but the actual monopoly starts when the patent is granted, typically around two years later. The application is made public no later than eighteen months after the filing of the application. If a patent is granted, the patentee can get compensation from unauthorized users of the invention as from the date of making public. An injunction and money remedies are available against unauthorized uses after the date of grant.