Letters Patent

Letters patent (no singular form exists) are a type of legal instrument in the form of a published written order issued by a monarch or president, generally granting an office, right, monopoly, title, or status to a person or corporation. They are so named from the Latin verb pateo, to lie open, exposed, accessible. They are called thus from their Latin name litterae patentes long used by mediaeval and later scribes when such documents were written in Latin, expressed in the plural, in the ancient sense of a collection of letters of the alphabet arranged to be read rather than in the modern sense of the word as an "epistle" or item of correspondence; thus no singular form exists.

Letters patent can be used for the creation of corporations or government offices, or for the granting of city status or a coats of arms. A particular form of letters patent has evolved into the modern patent granting exclusive rights in an invention. Clearly in this case it is essential that the written grant should be in the form of a public document so other inventors can consult it to avoid infringement.

The opposite of letters patent are letters close (Latin: litterae clausae), which are personal in nature and sealed so that only the recipient can read their contents.