papal bull

n. official Papal letter, formal declaration ithat the Pope issues

For specific bulls see List of papal bulls A Papal bull is a special kind of patent or charter issued by a pope. It is named after the seal (bulla) that was appended to the end to authenticate it. Papal bulls were originally issued by the pope for many kinds of communication of a public nature, but after the fifteenth century, only for the most formal or solemn of occasions. Modern scholars have retroactively used the term "bull" to describe any elaborate papal document issued in the form of a decree or privilege (solemn or simple), and to some less elaborate ones issued in the form of a letter. Popularly, the name is used for any papal document that contains a metal seal.
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Noun
1. a formal proclamation issued by the pope (usually written in antiquated characters and sealed with a leaden bulla)
(synonym) bull
(hypernym) decree, edict, fiat, order, rescript