Definition
Discretio is the Latin and Law Latin term for discretion as exercised within a legal framework — specifically, the power of a judge or legal officer to determine what is just and lawful in a given case. The term carries a precise meaning rooted in Roman and medieval English legal tradition: it is not the freedom to decide according to personal preference or whim, but the trained capacity to perceive and apply what the law requires. Discretio is the faculty of discernment bounded by law, not freed from it.
Common Language
Modern common usage (Wiktionary): The quality of behaving or speaking in such a way as to avoid causing offense or revealing private information; also, the freedom to decide something or the power to act on one's own judgment.
Historical common usage (Webster's 1913): "The quality of being discreet; wise conduct and management; cautious discernment, especially as to matters of propriety and self-control; prudence."
The gap between common and legal meaning is significant. In ordinary usage, discretion often implies personal latitude — the freedom to act as one sees fit. In the legal tradition represented by discretio, the concept runs in precisely the opposite direction: discretion is a form of disciplined perception, an exercise constrained and guided by law. The common usage emphasizes freedom; the legal usage emphasizes correctness within a framework.
Common Confusion
Discretio is frequently read by modern researchers as a Latin cognate of the modern English "discretion" and assumed to mean broad judicial freedom. This is the principal interpretive trap. The maxim preserved in Burrill — discretio est discernere per legem quid sit justum — makes the constraint explicit: discretion is to discern through the law what is just. The operative phrase is per legem, through or by the law. Discretio is not license; it is legal judgment. Conflating it with the modern concept of "wide discretion" — meaning a judge may do largely as she pleases within a range — misreads the historical sources and distorts the meaning of older authorities that invoke this term.
Why It Matters in Research
Researchers working in historical English legal materials, particularly Year Books, early common law treatises, and Coke's Institutes, will encounter discretio in contexts where modern editors or secondary sources have translated it simply as "discretion." That translation, without qualification, imports modern connotations that the original term does not carry. When Coke writes at 4 Institutes 41 — the source Burrill cites — the framework is emphatically one of law-bounded judgment, not unguided judicial will.
The distinction matters concretely in at least two research contexts. First, when tracing the historical development of the abuse-of-discretion standard, researchers must understand that the baseline conception of discretion in older authorities was already constrained; the modern standard did not invent the limitation but inherited and formalized it. Second, when reading equity cases and early prerogative writ materials, the presence of discretio or its English cognate in the sources signals a claim about the nature of judicial power — one that older courts took seriously as a jurisprudential matter, not merely a procedural one.
The 6 Q.B. 700 citation in Burrill connects discretio to Queen's Bench reporting and signals that the concept had active common law procedural currency well into the nineteenth century, not merely antique Latin ornament.
Historical Dictionary Support
Burrill's Law Dictionary provides a compact but precise treatment. The entry consists primarily of the maxim: discretio est discernere per legem quid sit justum — discretion is to discern by the law what is just. The citations anchor it to Coke (4 Institutes 41) and to Queen's Bench (6 Q.B. 700), giving the term both classical common law authority and mid-nineteenth-century English procedural relevance.
What Burrill does not address is the intellectual genealogy of the concept in Roman law and canon law, where discretio carried similar connotations of bounded judgment in ecclesiastical and civil administration. Researchers consulting only Burrill will get the operative English common law meaning but will miss the broader jurisprudential tradition from which the maxim draws. Historical dictionaries generally agree that discretio is not synonymous with arbitrium (will or arbitrary choice) — a distinction that Roman and medieval sources maintained carefully and that Coke's usage reflects.
Jurisdictional Note
Discretio as a term of art appears primarily in English common law sources and jurisdictions derived from that tradition. Civil law systems use related but distinct concepts (particularly arbitrium judicis and pouvoir discrétionnaire) that overlap in meaning but carry different doctrinal histories. Researchers working in comparative or mixed-jurisdiction materials should not assume direct equivalence.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Judicial Discretion; Abuse of Discretion; Equity and Judicial Power