letters patent

n. patent authorization, certificate of patent for an invention

Letters patent are a type of legal instrument in the form of an open letter issued by a monarch or government, granting an office, right, monopoly, title, or status to a person or to some entity such as a corporation. The opposite of letters patent (Lat. litterae patentes) is letters close (Lat. litterae clausae), which are personal in nature and sealed so that only the recipient can read their contents. Note that due to the Latin idiom involved, a single document is not a "letter patent" but still "letters patent."
See more at Wikipedia.org...

Noun
1. an official document granting a right or privilege
(synonym) patent
(hypernym) legal document, legal instrument, official document, instrument
(classification) law, jurisprudence

Document announcing an honor or power for an individual, granted by an official or nobleman . For example, arms might be granted by letters patent, or they might be granted lordship over a feudal estate.

-- see patent

Context: Patent