Definition
In Roman and civil law, triverbial days were the lawful court days on which a praetor was permitted to perform the three essential judicial acts of his office: pronouncing judgment, assigning a judge, and adjudicating a claim. The term derives from the three words — do, dico, addico — that the praetor was authorized to speak on such days. These three words corresponded to the praetor's core functions: do (granting a legal action or formula), dico (pronouncing a ruling), and addico (awarding or assigning a right). Days on which the praetor could not lawfully utter these words were nefasti, or non-juridical days. Triverbial days were also called dies fasti, the Roman term for days on which the courts could lawfully sit.
The concept belongs to the Roman calendrical system of court administration, which distinguished strictly between days when legal proceedings could occur and days when they could not. This distinction shaped the entire structure of Roman litigation timing.
Common Confusion
Triverbial days are sometimes loosely equated with all juridical or court days, but the term is more specific: it refers to days defined by the praetor's verbal authority to perform those three acts, not merely any day on which court business might proceed. The broader category is dies fasti; triverbial days are the mechanism that gives dies fasti their juridical character.
Why It Matters in Research
This term appears almost exclusively in historical and comparative legal sources. Researchers will encounter it in English commentaries on Roman law, in Blackstone's discussion of court days and legal process, and in civil law treatises reaching into the early American period, particularly those addressing the inherited structure of court calendars and juridical time.
The critical research trap is anachronism. Triverbial days have no direct operational counterpart in modern American or English common law. When the term surfaces in historical sources, it functions as a technical Roman law reference — often imported into English legal commentary to explain the conceptual origins of court-day restrictions or the formal boundaries of judicial authority. Burrill and both editions of Black's trace the term to Calvin's Lexicon and to Blackstone's Commentaries (Book 3), making those the primary textual sources to consult.
Researchers working in comparative law, legal history, or the foundations of civil procedure will find this term useful for tracing how the Roman idea that judicial power is time-bounded — that a judge does not simply possess authority but may exercise it only within defined temporal and formal limits — migrated conceptually into later legal systems. The idea that courts have prescribed sitting days, and that action taken outside those days may be void or irregular, has clear descendants in common law doctrine even where the Roman terminology was discarded.
For corpus researchers: the spelling varies between sources. Black's 1st edition and Burrill use "prætor" and "dies fasti" without always cross-indexing clearly, so searches for the related terms do, dico, addico and dies fasti will often retrieve the same conceptual territory more efficiently than searching on triverbial days alone.
Historical Dictionary Support
The three historical sources agree closely on substance. All three define triverbial days as juridical days on which the praetor could speak the three characteristic words of his office, and all three identify the words as do, dico, addico. All three cross-reference dies fasti as an alternative name. Burrill provides the most instructive entry, explicitly deriving the term from the Latin tria (three) and verba (words) and pointing readers to Calvin's Lexicon and to Blackstone's Commentaries at Book 3, page 424.
The Black's 2nd edition entry is essentially identical to the 1st, correcting a typographical artifact ("acords" for "words") but adding no new substantive content. Neither Black's edition provides the Latin derivation that Burrill supplies, which is a modest gap. No historical source in this set discusses the role of triverbial days in shaping later common law court-day doctrine — that connection requires consulting Blackstone directly rather than the dictionary entries alone.
Jurisdictional Note
Triverbial days are a Roman civil law concept with no current statutory or judicial existence in American or English law. The term appears in U.S. legal sources only as historical or comparative reference material, primarily in treatises and early commentaries that drew on Roman and civil law foundations.