From 14th Century Latin litterae patentes meaning literally an "open (official) letter".

From 12th Century latin litteræ see LETTER and patentes see PATENT.

A Letters Patent is similar in respect to a CHARTER in being used for official grants, titles, laws, right or monopoly and also in respect of honoring traditional form including the INCIPIT, the DATUM and the SEAL. However, Letters Patents may be on several pieces of paper and not velum (animal skin), may use black ink instead of red and a printed seal, instead of a BULLA.

As such a Letters Patent is always legally inferior to a proper CHARTER. The most common Letters Patent today are Degrees and Diplomas from Colleges and Universities, most of which fail to adhere to the valid legal form.