Definition
BULL carries two distinct legal meanings that share nothing but the word itself.
1. Ecclesiastical law. A formal instrument issued by the Pope of Rome, written on parchment and authenticated with a leaden seal (bulla) impressed with the images of Saints Peter and Paul. A bull constitutes an act of papal authority — functioning in canon law much as a royal edict or letters patent functions in secular government. Bulls may grant privileges, impose penalties, establish doctrine, or address matters of church governance. When a bull confers a favor or privilege, it is subject to interpretation in favor of the grantee; when it is penal in nature, it is construed strictly.
2. Stock exchange (historical cant). In financial usage, a bull is a speculator who purchases securities expecting prices to rise, intending to sell at a profit. The bull bets on upward movement; the bear bets on decline. This usage appears in early legal dictionaries as "a cant term of the Stock Exchange" and became embedded in commercial law discussions of exchange speculation and market manipulation.
Common Language
Modern common usage (Wiktionary): An adult male of domesticated cattle or oxen, particularly one uncastrated; also used for adult males of large mammals such as whales and elephants.
Historical common usage (Webster's 1913): The male of any species of cattle; by extension, the male of any large quadruped; also the zodiac sign Taurus.
The gap matters in two directions. First, a researcher encountering "bull" in ecclesiastical or canon law sources has nothing to do with cattle — the papal instrument is entirely a product of Latin administrative tradition. Second, the stock exchange usage is figurative slang that hardened into a recognized legal and commercial term; its common-language origin is the animal, but the legal career of the word in financial contexts is largely independent of it.
Recognized Forms
/SUBTYPES
Papal bulls are distinguished by purpose and form:
— Bulla solemnis: A formal bull issued for major pronouncements, bearing the full leaden seal.
— Brief (breve): A shorter, less solemn papal document, sealed differently; often confused with a bull but issued through the Papal Secretariat rather than the Chancery.
— Signature: A third class of apostolical rescript, simpler still.
Bouvier's Law Dictionary notes that of the three classes of apostolical rescripts — the brief, the signature, and the bull — the bull is the form most commonly encountered in legal matters.
Why It Matters in Research
Researchers face three distinct navigational challenges with this term.
First, corpus collision. A search for "bull" in Law Mind sources will surface ecclesiastical law materials, stock exchange materials, and — in older American treatises — agricultural and livestock statutes that use the word in its plain animal sense. These three streams do not overlap, and a researcher who fails to anchor the term in context will retrieve irrelevant results.
Second, the stock exchange meaning is time-sensitive. The phrase "cant term" signals that early legal dictionaries treated it as informal. By the late nineteenth century, discussions of exchange speculation in English and American treatises treat "bull" as a recognized term of art. Researchers examining market manipulation cases or exchange regulation from that period should expect the term to appear without explanation, as if its meaning were settled.
Third, papal bulls appear in American legal history primarily in three contexts: (a) colonial-era land grants and missionary authority in Spanish and French territories, where papal bulls may bear on chain-of-title questions; (b) ecclesiastical property disputes, where a bull may establish the authority of a diocese or order; and (c) historical commentaries on the relationship between church and state. Blackstone and Stephen's Commentaries, both cited by Black's, address bulls in the context of English statutes restricting their importation or enforcement — a regulatory layer that adds complexity when researching pre-Reformation or early colonial sources.
Historical Dictionary Support
All three source dictionaries converge on the ecclesiastical definition as primary, and all reference Blackstone (4 Bl. Comm. 110) and Stephen's Commentaries (4 Steph. Comm. 177, 179) as the authoritative English-law treatment. This agreement is significant: it places the papal bull firmly within the canon of English common law commentary rather than treating it as purely a foreign ecclesiastical curiosity.
Bouvier adds substantive detail that Black's omits: the distinction between favorable and penal bulls and their respective rules of construction. This is practically useful — Bouvier's entry is richer for researchers dealing with ecclesiastical property or privilege disputes.
The second edition of Black's introduces the stock exchange meaning alongside the ecclesiastical one, reflecting the growing importance of exchange regulation in late nineteenth-century American law. The first edition either omits this or treats it as incidental; the second edition's parenthetical note ("a cant term of the Stock Exchange") signals the term was gaining traction without yet being fully formalized.
What the historical dictionaries miss: none address the use of "bull" in livestock and agricultural statutes, which was widespread in American state law by the mid-nineteenth century and generated its own body of case law around straying animals, fencing obligations, and livestock licensing.
Jurisdictional Note
The ecclesiastical meaning has no operative force in U.S. federal law but remains relevant in states with significant Spanish or French colonial histories (Louisiana, California, Texas, New Mexico, Florida) where land grants and mission authority were shaped by papal instruments. The stock exchange meaning developed primarily in English and New York commercial law contexts.