Definition
In Roman civil law, trtverbial days (also rendered "triverbial days") were the days on which a Roman praetor was permitted to exercise his judicial functions — specifically, to pronounce the three solemn words of his office: *do* (I grant), *dico* (I declare), and *addico* (I adjudge). These three pronouncements constituted the core of the praetor's judicial power: granting an action or remedy, declaring the law, and adjudging the matter to a party. Days on which these words could lawfully be spoken were known as trtverbial days; days on which they could not were dies nefasti, on which public business was forbidden. Trtverbial days are synonymous with dies fasti — lawful or court days in the Roman calendar.
The term has no operative meaning in modern Anglo-American law. It appears in legal dictionaries primarily as a Roman law historical artifact, preserved to assist readers encountering the term in classical sources, early treatises, and commentaries that drew on Roman legal tradition.
Common Confusion
Trtverbial days should not be confused with the broader category of juridical days (dies juridici) in the general sense, though the terms substantially overlap. The distinction, where it exists, is that "juridical days" describes any day on which courts may lawfully sit, while "trtverbial days" refers specifically to the Roman praetor's authority to pronounce his three characteristic words. In most contexts — including Blackstone's Commentaries — the terms are used interchangeably, and no practical error results from treating them as synonyms.
The spelling "trtverbial" is itself an artifact of early typesetting conventions in which the ligature or letterform for "i" and "j" was rendered inconsistently. The intended word is triverbial, from Latin *tria verba* (three words).
Why It Matters in Research
Researchers are most likely to encounter this term in two contexts: (1) reading Blackstone's Commentaries, particularly Book III, which discusses the structure of English courts and draws comparisons to Roman procedure; and (2) reading early American treatises and digests that imported Blackstone's terminology wholesale. In neither context does the term carry operative legal weight — it is descriptive and historical, not a term that defines rights or procedures under Anglo-American law.
The variant spelling "trtverbial" — as it appears in the Black's Law Dictionary supplemental entry — is a direct product of OCR scanning or typographic reproduction of older print sources. Researchers searching historical databases should run searches on both "trtverbial" and "triverbial," as well as "tres verba" and "dies fasti," to capture the full range of source material.
The connection between trtverbial days and the concept of court days or juridical days in English and American law is loose but real. English equity courts and common law courts both observed calendars distinguishing sitting days from non-sitting days, and the Roman framework provided vocabulary for early commentators. A researcher tracing the historical development of court scheduling, judicial recesses, or the concept of dies non juridicus in American procedure will pass through this Roman antecedent.
There is no meaningful jurisdictional variation to note — the term is a Roman law relic without adoption into any American or English statutory scheme.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) defines trtverbial days as "[i]n the civil law. Juridical days; days allowed to the prætor for deciding causes; days on which the prætor might speak the three characteristic words of his office, viz., do, dico, addico," citing Calvin's dictionary and Blackstone's Commentaries, Book III, at 424. This entry is faithful to the Roman sources. The three words — do, dico, addico — are well attested in Roman legal history as the formulaic expressions of praetorian power, and the identification of trtverbial days with dies fasti is consistent with classical usage.
What Black's does not do — and what no historical legal dictionary fully addresses — is trace how, or whether, this Roman framework influenced the actual development of court-day rules in English common law. The connection is largely terminological rather than structural: English law developed its own rules about dies non juridicus, term days, and law terms independently of Roman calendrical law, even as commentators used Roman vocabulary to describe them.
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry directly addresses Roman civil law procedure or dies fasti. For adjacent procedural concepts involving court deadlines and filing days in modern practice, see: IRS Notice of Deficiency 90-Day Letter (The Law Mind Tax Encyclopedia); Federal Court Review — Standard of Review, Exhaustion, and the 30-Day Filing Deadline (The Law Mind Immigration Law Encyclopedia). These entries address modern juridical day-counting rules in specific federal contexts.