PRIVY SEAL, a seal of the United Kingdom, next in importance to the great seal, and occupying an intermediate position between it and the signet. The authority of the privy seal was principally of a two-fold nature. It was a warrant to the lord chancellor to affix the great seal to such patents, charters, etc., as must necessarily pass the great seal (more particularly letters patent (<?..). It was also the authority required for the issue of money from the exchequer, and was appended to documents of minor importance which did not require the great seal. Previous to the Great Seal Act 1884, all letters patent conferring any dignity, office, monopoly, franchise or other privilege were always passed under the privy seal before passing under the great seal.
Lord Privy Seal is the title of the officer who had the custody of the privy seal. He was originally known as the " keeper of the privy seal." The importance of the office was due to the desire of the privy council and the parliament in the 14th and 15th centuries to place some check on the issue of public money, as well as to prevent the use of the great seal by the sovereign without any intermediary except the lord chancellor. The lord privy seal first appears as a minister of state in the reign of Edward III. Until 1537 he was always an ecclesiastic, but is now more usually a temporal lord. He is the fifth great officer of state, and takes rank next after the president of the council and before all dukes.
See Anson, Law and Custom of the Constitution (1896).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)