letters patent. 1.Hist. A document granting some right or privilege, issued under governmental seal but open to public inspection. — Also termed literae patentes (lit-<<schwa>>r-ee p<<schwa>>-ten-teez). Cf. LETTERS SECRET. 2. A governmental grant of the exclusive right to use an invention or design. — Also termed (in both senses) patent deed. See PATENT(2). [Cases: Patents  1. C.J.S. Patents §§ 1–5, 10–12, 15.]

[Blacks Law 8th]