Definition
A Latin term meaning "about to show" or "who will show." In historical English legal practice, *ostensurus* functioned as a formal term of art appearing in old writs, where it introduced the obligation of a party to produce or demonstrate something before the court — whether a document, a right, or a cause of action. The word is the future active participle of the Latin *ostendere* (to show), and its placement in a writ carried the procedural force of a formal undertaking to exhibit or prove.
Why It Matters in Research
This term will appear only in pre-modern English writ forms and related procedural texts. Researchers encountering *ostensurus* in historical sources should understand it as a formulaic word with no independent substantive legal meaning — its significance is structural. It signals the point in a writ where the party (typically the plaintiff or demandant) formally commits to demonstrating the basis of their claim or the instrument upon which they rely.
For corpus researchers, the key traps are two. First, *ostensurus* is easily overlooked as mere Latin filler in transcribed writs, when in fact its presence confirms the document's writ form and procedural posture. Second, because the term appears in Registrum Omnium Brevium (the Register of Writs) and related formularies, its presence can help date and categorize a source: registers and form books using this language are products of the medieval and early modern English common law system, before writ pleading was abolished by the Common Law Procedure Acts of the mid-nineteenth century. Finding it in a source later than that period likely indicates a historical reprint, a scholarly commentary, or a formulary reproduced for reference purposes.
The term has no meaningful life in American legal practice or sources. Researchers working in colonial American records may encounter it in documents following English writ forms, but it carries the same formulaic weight rather than any adapted American meaning.
Historical Dictionary Support
Burrill's Law Dictionary provides the entirety of the recorded lexicographic treatment: "L. Lat. To show. A formal word in old writs. Reg. Orig. 36. Fet Assaver, § 21." The entry is brief by design — Burrill correctly identifies the term as functional rather than substantive and does not attempt to inflate its significance. The citations to *Registrum Omnium Brevium* (Reg. Orig.) and *Fet Assaver* ground the term in its proper formulary context.
No other major historical law dictionaries in the Law Mind corpus treat *ostensurus* as a primary entry. Its absence from later dictionaries reflects the obsolescence of writ pleading rather than any error or omission — by the time Bouvier and Black were producing their influential editions, the formal writ system that gave the word its procedural home had been substantially dismantled by statute. Researchers should not expect to find expanded treatment elsewhere and should treat Burrill's entry as the terminal point of the term's dictionary history.
Jurisdictional Note
Exclusively an English common law term rooted in the medieval writ system. It has no recognized presence in civil law jurisdictions and no independent American legal history, though it appears in colonial-era documents modeled on English forms.