Definition
A Latin term of medieval legal usage meaning a horse equipped with saddle and riding furniture — that is, a horse furnished and ready for use, as distinguished from a bare or unequipped horse. The term appears in feudal records, inventories of property, and documents governing the obligations of tenants and vassals where the type and condition of horses owed or transferred had practical legal and military significance.
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Common Language
Modern common usage (Wiktionary): No entry. The term does not appear in modern general usage.
Historical common usage (Webster's 1913): No entry. The term is Latin and did not pass into English common vocabulary.
The phrase is pure legal-Latin of feudal provenance. There is no meaningful gap between common and legal meaning to reconcile — the term simply has no life outside specialized historical and legal sources.
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Why It Matters in Research
Researchers encountering equus coopertus will almost certainly find it in one context: transcriptions or translations of medieval feudal records, inquisitions, inventories post mortem, or tenure documents, where the distinction between a caparisoned or furnished horse and an unequipped one carried real consequences for what a tenant owed his lord or what an estate's assets comprised.
The critical research trap is treating all references to horses in feudal documents as interchangeable. Period sources distinguished carefully between grades and furnishings of horses — equus, runcinus (a work horse or hackney), affrus (a farm horse), and dextrarius (a destrier or war horse) — and whether equipment was included bore directly on the value and nature of the obligation described. A reader who does not notice equus coopertus as a term of art may misread the scope of a military service obligation or the valuation in a property record.
The Rapalje & Lawrence entry references Du Cange — meaning Glossarium Mediae et Infimae Latinitatis by Charles du Fresne, sieur du Cange, the indispensable authority for medieval Latin legal terminology. Researchers working with primary feudal sources should consult Du Cange directly for fuller treatment than any English legal dictionary provides. The citation to 1 Phillim. 417, 466 appearing in the Rapalje & Lawrence entry attaches to the immediately following term ERASE, not to equus coopertus; researchers should not apply that citation to this term.
Because equus coopertus is a term of art from English and continental feudal practice, it will not appear in American legal records and is unlikely to appear in any post-medieval English legal proceedings outside antiquarian or historical arguments. Its appearance in a research corpus almost always signals a document of medieval provenance or a treatise discussing feudal tenures.
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Historical Dictionary Support
All three source dictionaries — Black's (1st ed.), Black's (2nd ed.), and Rapalje & Lawrence — give identical, minimal definitions: a horse equipped with saddle and furniture. There is no divergence among sources, nor any elaboration. None of the entries provides historical context for how the term functioned in feudal legal practice, what documents it appeared in, or how it related to the broader taxonomy of horses in medieval law. The consistent brevity reflects the term's narrow utility: it was preserved in English legal dictionaries principally because English feudal records written in Latin required it.
The Rapalje & Lawrence entry is marginally more informative in pointing toward Du Cange as the authoritative source, which appropriately directs researchers toward the correct scholarly tool for this class of terminology. Modern researchers needing substantive engagement with this term will find more in Du Cange and in secondary literature on English feudal tenures than in any of the shelf dictionaries.
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Jurisdictional Note
Equus coopertus is exclusively a term of medieval feudal law, applicable to English and continental European legal records from that period. It has no recognized application in any modern jurisdiction.
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