Definition
A Latin term meaning "money" or "a coin," used in Roman and civil law sources to denote currency generally or, in some contexts, a specific unit of monetary value. In legal texts, nummus carries two functional meanings:
1. As a general term: Money in the abstract — the medium of exchange recognized and given effect by law. In this sense, nummi encompasses currency of all kinds and appears in legal instruments, contracts, and pleadings where the obligation concerns a monetary sum.
2. As a nominal or token sum: A single coin of minimal value, used in legal transactions and formulae to signify a purely symbolic price or consideration — the Roman-law equivalent of the common law "peppercorn." A sale for one nummus (emptio pro uno nummo) was a recognized device in Roman law for effecting transfers where no real price was intended.
Common Language
Modern common usage (Wiktionary): Any of a range of low-value copper coins issued by the Roman and Byzantine empires during Late Antiquity.
Historical common usage (Latin): A piece of money, a coin, money generally. Used freely in classical Latin to mean both a specific small coin and currency at large.
The gap between the numismatic and legal meanings matters to researchers. In historical legal sources, nummus rarely refers to a specific denomination or physical coin. It functions instead as a legal abstraction — money as a concept authorized by law, or a token consideration in a formal transaction. Treating it as a reference to a particular coin type, as the common usage suggests, will misread the doctrinal point.
Common Confusion
Nummus is sometimes read as though it carries the narrow meaning of a low-value copper coin (its meaning in late antique numismatics) when appearing in Roman-law texts. The legal sources use it far more broadly. Conversely, modern readers familiar with the common-law concept of nominal consideration may assume the token-sum usage of nummus is a quirk or fiction; in Roman civil law it was a recognized and substantively operative device, not merely a formality without legal consequence.
Why It Matters in Research
Researchers working in Roman law, civil law jurisdictions, or the history of contract and property will encounter nummus in source texts and translations. Several research traps are worth flagging.
First, the word's appearance in a contractual or conveyancing context does not automatically signal a real monetary obligation. When a source reads "pro uno nummo" or similar, the researcher should treat it as a possible nominal-consideration formula rather than evidence of an actual one-coin price.
Second, Burrill's derivation note — tracing nummus to the Greek nomos (law) — reflects a jurisprudential claim that money derives its force from legal authority rather than intrinsic value. This is not merely etymological curiosity; it connects to longstanding debates in legal philosophy and monetary theory that surface in later civil law commentary and occasionally in Anglo-American currency jurisprudence. The competing derivation from numerus (number) reflects the alternative view that money is essentially a counting and accounting device. Both threads appear in historical legal argument, and knowing that Burrill flags this divergence helps researchers locate the doctrinal stakes.
Third, corpus searches for nummus in Latin legal texts will return hits across very different registers — general monetary references, nominal-consideration clauses, and philosophical discussions of what money is. Disambiguating these requires attention to context rather than relying on the word alone as an index of subject matter.
Fourth, the term connects the Roman-law tradition directly to civil law jurisdictions that inherited and codified Roman contract doctrine. Researchers tracing nominal consideration, simulated sales, or the requirements for a valid pretium in civil law systems will find nummus at the conceptual root of those discussions.
Historical Dictionary Support
Burrill's entry is brief but pointed: "Money. Commonly derived from Gr. νόμος, law, as being originally established by law." The citation to Coke (Co. Litt. 207b) is notable — it places nummus not only in Roman-law scholarship but in the English common law tradition, where Coke's Institutes engaged with Roman and civil law sources on monetary questions. The alternative derivation from numerus, attributed to Calvin's Lexicon Juridicum, is a genuine scholarly divergence that Burrill preserves rather than resolving.
What Burrill does not address is the token-consideration use of nummus in Roman transactional practice, which is well attested in the Digest and in the classical commentators. For that dimension, Burrill's entry must be supplemented by Roman law sources directly. The Latin dictionary tradition (as represented by Lewis and Short) confirms the broad monetary meaning while also documenting specific uses in Cicero, Plautus, and Horace — literary and forensic contexts that legal researchers may encounter when tracing a term through non-legal classical sources.
No significant divergence among the available historical legal dictionary sources exists here, as Burrill is the sole entry in the corpus for this term.
Jurisdictional Note
Nummus as an operative legal term belongs to Roman law and the civil law tradition descended from it. It does not appear as a term of art in Anglo-American common law, though Coke's engagement with it shows awareness of the concept. Researchers in Louisiana, Quebec, and other mixed or civil law jurisdictions may encounter the term in foundational doctrinal sources; in purely common law jurisdictions it appears only in historical and comparative contexts.