Definition
A term from Roman civil law denoting an innkeeper — a person who kept a public house or tavern and received travelers for lodging and food in exchange for payment. The caupo occupied a defined legal role in Roman law, particularly under provisions governing the liability of those who received goods or property belonging to guests. Under the Digest, a caupo bore responsibility for loss or damage to property brought onto the premises by travelers, a liability that arose from the public and quasi-official character of the innkeeping trade rather than from any specific contractual undertaking.
Common Language
Modern common usage (Wiktionary): No standard entry; the term does not survive in ordinary modern English.
Historical common usage (Webster's 1913): Not recorded. The term was already archaic in general English usage by the nineteenth century, surviving only in legal and classical scholarly contexts.
The gap here is one of survival rather than divergence: caupo never entered common English usage at all. Its appearance in legal texts is entirely a function of the civil law tradition's influence on Anglo-American legal scholarship, particularly in discussions of innkeeper liability.
Common Confusion
Caupo is sometimes encountered in close proximity to related Roman law terms — stabularius (stable-keeper) and nauta (sailor or shipmaster) — because all three appear together in the same title of the Digest (D. 4.9) as parties subject to the actio in factum for loss of guests' property. Researchers should not treat these as synonyms. The caupo kept an inn; the stabularius kept a stable for animals; the nauta commanded a vessel. Their liability rules were analogous but applied to distinct commercial relationships. Burrill's entry, which trails into unrelated material on causa proxima, reflects a transcription artifact and should not be read as substantively connecting caupo to proximate cause doctrine.
Why It Matters in Research
Caupo surfaces almost exclusively in two research contexts: (1) historical treatments of innkeeper liability, and (2) civil law glossaries and Digest commentaries. Researchers tracing the doctrinal lineage of modern innkeeper liability — including the common law rules on a hotelkeeper's strict or near-strict liability for guest property — will find caupo at the Roman root of that tradition. The Digest title D. 4.9 (Nautae caupones stabularii ut recepta restituant) is the foundational text, and caupo is the specific actor within that framework relevant to lodging.
A practical trap: because caupo appears in the Digest alongside nauta and stabularius, nineteenth-century treatise writers sometimes discussed all three together when explaining the origins of common carrier and innkeeper liability. A researcher focused on carrier law may encounter caupo in passing without it being directly relevant to that inquiry. Conversely, a researcher focused on innkeeper law who searches only English-language terms may miss important doctrinal history if they do not recognize caupo as the civil law antecedent.
The term does not appear in equity or common law pleading as a technical term of art. Its presence in an American or English legal text is almost always a signal that the author is drawing on civil law sources or making a comparative argument.
Historical Dictionary Support
Black's (both editions) and Burrill agree completely on the core definition: caupo means innkeeper in the civil law, and both cite Digest 4.9.4.5 as the authority. There is no divergence among the historical sources on meaning.
Burrill's entry is corrupted in available transcriptions — it runs into unrelated material on causa proxima and a quotation from Justice Grier — but this is an artifact of compilation rather than evidence of any substantive connection between caupo and those doctrines. Researchers using Burrill should be aware that the caupo entry as it appears in some digital versions is unreliable as a standalone text.
What the historical dictionaries do not address: the specific nature of the liability the caupo bore, the procedural vehicle (the actio in factum), or the policy rationale behind imposing liability on innkeepers as a class. For that substance, researchers must go directly to the Digest or to civilian commentators such as Pothier or Domat, whose works influenced both American and English treatments of innkeeper law.
Jurisdictional Note
Caupo is a term of Roman civil law with no direct operative meaning in any modern common law jurisdiction. Its relevance in American and English legal research is entirely historical and comparative. Louisiana, as a civil law jurisdiction, has a closer textual relationship to the underlying Digest provisions, but even Louisiana practice does not use caupo as a term of art.