Definition
Latin. A rule. In legal usage, *regula* carries two distinct contexts:
1. In practice (common law courts): A rule of court — a standing order or procedural directive issued by a court to govern practice before it. Frequently appears in the abbreviated form "Reg. Gen." when referring to a *regula generalis* (a general rule of court).
2. In Roman and civil law: A legal maxim or doctrinal rule of general application. The Digest of Justinian defines the term with characteristic precision: *regula est quae rem quae est breviter enarrat* — a rule is that which briefly sets forth the subject matter. The seventeenth title of Book 50 of the Digest (*De Diversis Regulis Juris Antiqui*, "Of Divers Rules of the Ancient Law") is the classical repository of such maxims and was a foundational text for civilian jurists.
Recognized Forms
/SUBTYPES
REGULA GENERALIS — A general rule or standing order of a court, as distinguished from a rule issued in a particular case. Abbreviated "Reg. Gen." in older English practice materials.
REGULA CATONIANA — A specific Roman law rule governing the validity of testamentary dispositions. Named for the jurist Cato. The substance: a bequest void at the time of the will's making cannot be validated by any subsequent change of circumstances. See Digest 34.7.
Why It Matters in Research
Researchers encounter *regula* in two distinct corpora, and conflating them creates confusion. In older English common law materials — writs, court records, and practice guides from the sixteenth through nineteenth centuries — *regula* and *regula generalis* refer to procedural court orders. These are administrative instruments, not substantive legal principles. When an old chancery or King's Bench record references a *reg. gen.*, it is pointing to a standing procedural directive, not a legal maxim.
In civil law and Roman law scholarship, *regula* is a term of art for a doctrinal maxim abstracted from case outcomes. Digest 50.17 is the canonical source. Researchers working in jurisdictions with civil law heritage — Louisiana, Quebec, mixed systems — will find *regula* invoked in this sense in both historical and modern materials. The distinction between a *regula* as a descriptive summary of law and a *regula* as a binding rule (in the modern sense) is itself a classical debate: Justinian's compilers were careful to note that rules derived from law, not law from rules.
The abbreviation "Reg. Gen." in English practice materials can generate confusion in catalog and index searches, as it may be parsed as a reference to a person, a register, or a general regulation rather than a court order.
Historical Dictionary Support
The historical sources agree on the dual usage but distribute their attention differently. Black's (both editions) and Burrill cover both the practice meaning and the civil law meaning, with Burrill quoting Digest 50.17.1 directly — a useful anchor for researchers tracing the Roman law usage. Black's adds the *Regula Catoniana* as a notable named application. Bouvier redirects entirely to MAXIMS, which is editorially appropriate: in Bouvier's framework, *regulae juris* are treated as a subset of maxims, and his maxims table is where the substance lives. Anderson offers no definition of its own, cross-referencing REGULAR and related entries — less useful, but consistent with his condensed format.
None of the historical dictionaries engage the classical jurisprudential tension around *regulae* — the debate among Roman jurists about whether rules were truly prescriptive or merely descriptive summaries. For that, researchers should consult civilian treatises and commentary on Digest 50.17 directly.
Jurisdictional Note
In common law jurisdictions, *regula* as a live term of art has largely been displaced by "rule of court" in modern practice. In civil law systems and mixed jurisdictions, *regula* and *regulae juris* retain scholarly currency, particularly in discussions of legal maxims and interpretive canons.