Definition
Dies non (short for dies non juridicus, "a day not judicial") is a day on which courts do not sit and legal business is not transacted. On a dies non, the ordinary machinery of litigation pauses: deadlines that fall on such a day are tolled, and procedural acts performed on that day may be void or treated as if done on the next valid court day.
The category encompasses Sundays, public holidays designated by statute or court rule, and any other day on which a court is officially closed. The practical consequence is uniform: a dies non does not count in the computation of procedural time periods, and it does not extinguish a right or obligation whose deadline would otherwise fall on that day.
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Common Language
Modern common usage (Wiktionary): "A day on which courts are not held."
Historical common usage (Webster's 1913): "A day on which courts are not held, as Sunday or any legal holiday."
The common definitions are accurate as far as they go, but they omit the operational legal consequence that makes the term matter: not merely that courts are closed, but that a dies non suspends the running of procedural time, shifts filing deadlines forward, and may nullify legal acts performed on that day. The common definitions describe the status; the legal term carries a rule about consequences.
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Common Confusion
Dies non is sometimes loosely treated as synonymous with "holiday" or "court holiday." The distinction is precise: a holiday is a designated non-working day; a dies non is any day the court does not transact judicial business, which may include emergency closures, judicial emergencies, or days when no judge is available. Not every holiday is universally a dies non in every jurisdiction, and historically some religious observances functioned as dies non even without explicit statutory designation. Researchers working in historical sources should not assume modern holiday calendars map cleanly onto historical dies non classifications.
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Why It Matters in Research
The term matters most when computing deadlines in historical litigation records. When a statute or court rule specifies that an act must be done within a fixed number of days, any dies non falling within that period was traditionally excluded from the count. Researchers tracing the history of a case must reconstruct which days qualified as dies non in the relevant jurisdiction at the relevant time — a reconstruction that requires consulting historical court calendars, local rules, and sometimes ecclesiastical calendars in pre-modern English sources.
In English common law tradition, dies non juridici included not only Sundays but also numerous holy days and the four legal vacations (the periods between law terms). American practice simplified this considerably, eventually codifying specific categories of excluded days by rule, but the underlying concept carried forward. Corpus users working in eighteenth- and nineteenth-century American practice will encounter both the English term and its shortened form used interchangeably, sometimes with inconsistent application across state courts.
A practical trap: some historical instruments — deeds, bills of exchange, promissory notes — were dated on a dies non. Courts generally construed the instrument as if executed on the next valid day, but this was a question of construction, not automatic operation, and the outcome was not uniform. Researchers should not assume that an instrument dated on a Sunday or holiday was void; it was more commonly simply re-dated by legal construction.
Procedural deadline research is the core use case for this term. Modern court rules have largely replaced the concept with explicit statutory language ("if the last day falls on a Saturday, Sunday, or legal holiday, the period runs until the end of the next day which is not a Saturday, Sunday, or legal holiday"), but historical pleadings and motions invoking dies non operate under the older framework.
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Historical Dictionary Support
Black's Law Dictionary and Burrill's Law Dictionary treat dies non as a straightforward abbreviation of dies non juridicus and cross-reference that full entry. Neither elaborates beyond the abbreviated form, leaving the substantive legal content to the parent entry. This is consistent treatment, appropriate to a short-form cross-reference entry, but researchers relying on the abbreviated form alone will need to pursue the full entry for operative doctrine.
Bouvier's entry, as preserved in the source material, focuses on instrument dating and construction — specifically the rule that courts will construe instruments to uphold bona fide transactions when computing time. This is a related but distinct application of dies non principles, showing Bouvier's characteristic attention to transactional practice alongside procedural law.
Rapalje & Lawrence's source excerpt appears to have been misdirected (the visible text concerns a statute about magistrates selling victuals) and does not yield usable content on dies non. Researchers should not rely on Rapalje & Lawrence as a primary source for this term.
Historical sources collectively agree on the core definition but are sparse on the American procedural implementation. The rich common law elaboration of dies non — including the full calendar of English law terms and their vacations — is better sourced in English legal dictionaries and treatises such as Blackstone's Commentaries and Tidd's Practice than in the American dictionaries on the Law Mind shelf.
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Jurisdictional Note
American jurisdictions have codified dies non principles in court rules and statutes governing computation of time, making the Latin term largely vestigial in modern practice. Federal practice is governed by Federal Rule of Civil Procedure 6(a), which controls time computation and excluded days. State rules vary; researchers working in state court records should consult the applicable state rules of civil procedure for the relevant period.
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