Definition
Rem is a Latin accusative form of res (thing), meaning "the thing" or "a thing." It does not stand alone as a term of art but appears as an essential component of several Latin phrases with independent legal significance. The two most important are:
1. In rem. Literally "against the thing." Describes a legal action, proceeding, or judgment directed at property itself rather than at a specific person. An in rem judgment binds the world with respect to the property's status or disposition, regardless of whether every interested party was personally served.
2. Jus in re. Literally "right in the thing." A real right — a right exercised directly over a thing, as distinguished from a personal right (jus ad rem, a right to acquire the thing). Jus in re propria denotes full ownership or the right of enjoyment incident to complete dominion over one's own property. Jus in re aliena denotes a lesser real right over another's property, such as an easement or usufruct.
Common Language
Modern common usage (Wiktionary): REM as an initialism stands for "rapid eye movement," a phase of the sleep cycle associated with dreaming.
Historical common usage (Webster's 1913): Rem does not appear as an independent English entry in Webster's 1913; it was understood as a Latin word meaning "thing" (accusative of res).
The legal rem is not an English word — it is a Latin grammatical fragment that only acquires meaning inside fixed legal phrases. Researchers encountering "rem" in isolation in a legal source should immediately look for its governing preposition (in rem, ex rem) or genitive construction (jus in re) to determine meaning. Confusion with the modern initialism is harmless in practice but signals that a source has stepped outside legal Latin entirely.
Common Confusion
Rem vs. Res. Anderson's Dictionary of Law cross-references rem directly to res, and this points to the core confusion: res is the nominative form (the subject), rem is the accusative form (the object of a preposition or verb). Most legal dictionaries index the concepts under res, so researchers searching for rem may find only a redirect. The substantive doctrine — property, the thing at issue, the subject matter of litigation — is discussed under res. Rem surfaces in fixed prepositional phrases, particularly in rem, where it cannot be replaced by res without breaking the Latin grammar. Do not treat them as interchangeable entries; treat rem as a pointer directing research to res and to in rem as a separate compound entry.
Why It Matters in Research
The practical research significance of rem lies almost entirely in the phrase in rem and its contrast with in personam. In admiralty and maritime law, the in rem action against a vessel is the foundational enforcement mechanism for maritime liens — a ship may be arrested to satisfy a lien regardless of who currently owns it. This is the procedural core addressed in the linked encyclopedia entry. Researchers in the Law Mind corpus will encounter rem most heavily in admiralty materials, property law discussions of real rights versus personal rights, and constitutional due process literature addressing the notice requirements for in rem jurisdiction.
Historical sources present a trap: older equity and common law texts use in rem loosely to mean any proceeding affecting status or property, but modern jurisdictional doctrine has refined the category. The Supreme Court's Shaffer v. Heitner line of analysis (requiring minimum contacts even for in rem jurisdiction) fundamentally changed what older treatises assumed. A researcher relying on pre-1977 sources for in rem jurisdictional rules will find statements that are no longer constitutionally accurate.
The jus in re / jus ad rem distinction, prominent in Black's and Burrill, was central to feudal property analysis and appears frequently in older title and conveyancing materials. It has diminished practical significance in modern American property law but remains essential for reading 18th and 19th century sources accurately. Conflating jus in re (existing real right) with jus ad rem (inchoate right to acquire) can cause serious misreading of historical title chains.
Burrill's note on remanet — tracing it to a Latin couplet in Fleta about priority of sale — illustrates how rem-based Latin phrases generated modern procedural vocabulary. Researchers in historical English practice will encounter remanet as a term for a case held over to the next term; its Latin root connects it etymologically to this cluster.
Historical Dictionary Support
The historical dictionaries approach rem from different angles, none treating it as a fully independent entry.
Black's (1st and 2nd editions) discuss rem almost exclusively through the lens of jus in re, providing the propria / aliena distinction as the organizing principle of real rights. The 2nd edition is more precise, explicitly contrasting jus in re propria (full ownership's enjoyment right) with jus in re aliena (easement or lesser right over another's property). Both editions quote the maxim jus in re inhærit ossibus usufructuarii — the right in the thing cleaves to the bones of the usufructuary — to illustrate that real rights follow the person who holds the interest, not merely the document evidencing it. This maxim has direct relevance to understanding why a usufruct survives transfer attempts that purport to strip it.
Anderson offers only a redirect to res, which is editorially sound: the doctrine lives at res, and rem is a grammatical variant. Researchers should follow that redirect for substantive doctrine.
Burrill is the most historically textured, connecting rem to Fleta and tracing how Latin usage in medieval sources gave rise to English procedural terms. This is valuable context for anyone working in legal history or early common law sources.
What the historical dictionaries do not address: the constitutional due process dimension of in rem jurisdiction, the admiralty arrest procedure, and the Shaffer v. Heitner refinements. For any modern jurisdictional question, historical dictionary entries are starting context only.
Jurisdictional Note
In rem jurisdiction and procedure vary between federal and state courts. Federal admiralty in rem practice is governed by the Supplemental Rules for Admiralty or Maritime Claims and Asset Forfeiture Actions (appended to the Federal Rules of Civil Procedure). State courts exercising quasi-in-rem jurisdiction over property must now satisfy constitutional minimum contacts requirements that did not exist under the older territorial theory. Civil law jurisdictions use analogous concepts of real rights (droits réels, derechos reales) but the procedural mechanisms differ substantially from common law in rem actions.
Encyclopedia Cross-Reference
Maritime Liens — Creation, Priority, and Enforcement Through In Rem Arrest (Law Mind Military, Veterans & Admiralty Law Encyclopedia)