Definition
Jus commune (Latin: "common right" or "common law") carries two distinct but related meanings depending on context:
1. In Roman and civil law: The general, ordinary rules of law applicable to all persons equally, as distinguished from jus singulare — the exceptional or privileged rules introduced for particular persons or circumstances. Jus commune in this sense represents the baseline of legal right from which departures must be justified. A person may renounce rights introduced for their own benefit that operate against the jus commune, but the jus commune itself stands as the default framework.
2. In English law: The common law of England, functioning as the body of general legal rules applicable to the community at large. In this sense it corresponds to the Saxon "folcright" — the law of the folk, or the people's law — and stands in contrast to special or local customs. Blackstone uses the term in this second sense.
The two usages share a common conceptual core: general law applicable broadly, as opposed to exceptional, special, or privileged law. A researcher must identify which legal tradition is being invoked before the term's meaning becomes precise.
Common Confusion
The phrase is easily conflated with "common law" in the Anglo-American sense, but the overlap is imperfect. When civil law writers use jus commune, they mean Roman law's general rules, not English judge-made law. When Blackstone uses jus commune, he means English common law specifically. In Continental European legal history, jus commune also refers to the pan-European learned law tradition — Roman and canon law as taught in medieval universities and applied across jurisdictions — a usage none of the historical dictionaries in this corpus address directly. Researchers working across civil and common law sources, or in comparative or ecclesiastical law contexts, must be alert to which layer of meaning is operating.
Why It Matters in Research
This is a term where context determines meaning, and historical sources do not always signal the shift clearly. Several research traps are worth flagging:
First, the civil law meaning (general rule vs. exceptional rule) and the English law meaning (common law as a system) are structurally different. A passage citing jus commune in a treatise on Roman law is saying something about the architecture of legal rules; the same phrase in an English common law treatise is naming a legal system. Misreading the context produces errors.
Second, in the broader history of European law, jus commune refers to the shared learned law tradition of Roman and canon law that operated across medieval and early modern Europe as a kind of supranational legal substrate. This usage — important in comparative law, legal history, and ecclesiastical law research — is entirely absent from the Anglo-American historical dictionaries in this corpus. Researchers following citations into Continental sources, canon law materials, or comparative legal history will encounter this third meaning and will not find it scaffolded here.
Third, the opposition to jus singulare is analytically important. Many historical legal arguments turn on whether a rule is part of the jus commune (generally applicable, presumed to apply) or jus singulare (exceptional, requiring specific justification). Researchers encountering this opposition in Roman law texts, Bracton, or civil law treatises should treat the terms as a pair. Look for the jus singulare entry for the counterpart concept.
Fourth, the Bracton citation in Burrill is significant. Bracton's use of jus commune shows the term migrating from Roman into English legal writing, carrying its civil law sense. Researchers in medieval English legal history will find the term operating in this hybrid space, neither purely Roman nor purely English in its connotations.
Historical Dictionary Support
The corpus sources converge on the two core meanings without significant disagreement, though their emphases differ. Burrill provides the most detailed civil law treatment, citing Mackeld and the Digest directly, and preserving the Bracton reference that bridges civil and English usage. Black's second edition is the only source to explicitly invoke Blackstone and the Saxon "folcright," grounding the English law meaning in a specific historical context. Bouvier adds a useful phrase — "applicable to all persons alike" — that captures the universality implicit in the civil law sense.
What the corpus uniformly omits is the Continental jus commune tradition: the idea of a shared learned law operating across European jurisdictions from roughly the twelfth through seventeenth centuries. This absence reflects the Anglo-American orientation of these dictionaries, but it means the corpus under-serves researchers in comparative law, medieval legal history, and canon law who will encounter this usage frequently in primary and secondary sources.
The maxim preserved in Rapalje and Black's second edition — that laws ought to be made with a view to what happens most frequently, not rare or accidental occurrences — is not a definition of jus commune itself but a related principle that appears in proximity in the Digest. Researchers should not treat it as definitional.