Definition
A Latin term from Roman civil law meaning "public" — that is, belonging to or available for use by the people at large, as distinguished from things owned by private individuals or held in common. In its primary application, *publicus* describes the legal status of certain natural and man-made features — rivers, harbors, riverbanks — that are open to public use by their nature and cannot be reduced to private ownership.
The term operates as a classification within the Roman law of property, sorting things (*res*) into categories based on who may use them and how. Things that are *publica* belong, in a broad sense, to the state or people, but the practical content of that status is the entitlement of any member of the public to use them — for navigation, commerce, fishing, or passage — rather than formal state title in the modern sense.
Why It Matters in Research
Researchers encountering *publicus* in historical legal materials are working within a taxonomy of property that does not map cleanly onto modern American or English property law. The critical research trap is assuming that *publicus* equates to "government-owned" in the contemporary sense. Roman law distinguished between *res publicae* (things belonging to the Roman people as a political body), *res communes* (things common to all by nature, like air and the sea), *res universitatis* (things belonging to municipalities), and *res privatae* (private things). *Publicus* applies specifically to the first category, but Bracton and later English writers borrowed the vocabulary imprecisely, sometimes collapsing *publica* and *communia* in ways that create ambiguity in medieval English sources.
The Bracton distinction flagged in Burrill — between "public" and "common" — is a key analytical pivot. Bracton, writing in thirteenth-century England, recognized that rivers could be simultaneously public (in that the crown or the realm held them) and common (in that all subjects had use-rights). These are not synonymous. A researcher tracing the public trust doctrine, riparian rights, or the legal status of navigable waters in historical English or American sources must hold this distinction clearly, because conflation of *publicus* and *communis* has generated centuries of doctrinal confusion about whether the state owns navigable waterways, holds them in trust, or merely administers a public right of use.
*Publicus* appears in foundational passages of Justinian's *Institutes* and *Digest* that are cited repeatedly in early American water law and tidelands cases. Understanding the term's Roman meaning is often necessary to assess how faithfully later jurists actually followed the civil law sources they cited.
Historical Dictionary Support
Burrill's treatment is brief but precise. He correctly identifies the civil law origin, supplies the key Justinianic texts (*Institutes* 2.1.2 and 2.1.4; *Digest* 1.8.4.1 and 1.8.5), and cross-references Bracton's *De Legibus et Consuetudinibus Angliae* (fol. 8). The maxims quoted — *flumina omnia et portus publica sunt* (all rivers and harbors are public) and *riparum quoque usus publicus est* (the use of riverbanks is also public) — are genuine Roman law texts and appear throughout the civil law tradition.
Burrill's most important contribution is the parenthetical note that Bracton draws a distinction between "public" and "common," with a cross-reference to his own entry for COMMON. This is analytically significant and reflects genuine scholarship: Bracton was working with Roman categories in an English common law context and was careful enough to note the difference, even if later English and American jurists often were not.
What Burrill does not do — and what his format did not require — is explain the full taxonomy of Roman property classification or trace how *publicus* migrated into English riparian doctrine. Researchers should not treat his entry as a complete account of the term's legal career.
Jurisdictional Note
The term belongs to Roman civil law and appears in English legal sources primarily through Bracton and subsequent citations to the *Institutes* and *Digest*. Its most persistent modern relevance is in American public trust doctrine and navigable waters law, where courts in civil law states (particularly Louisiana) and in federal admiralty and tidelands jurisprudence have relied on the Roman classification. Common law jurisdictions generally absorbed the concept through equity and statute rather than through direct Roman law application.