Definition
Fungibiles (also fungible things) are items of such a nature that any unit is interchangeable with any other unit of equal quantity and quality. A thing is fungible when it can be replaced by another thing of the same kind and measure without loss or distinction — one bushel of wheat stands in for another, one dollar bill for another, one barrel of oil of the same grade for another. The term derives from Roman civil law and remains foundational in property, contract, and commercial law.
The defining characteristic is substitutability. A specific horse, a named painting, or an identified parcel of land are not fungibiles because no substitute unit is equivalent to the original. Grain stored in a common silo, currency, standardized commodities, and negotiable instruments generally are.
Common Confusion
Fungibiles is the Latin civil law form. Modern legal writing uses fungible or fungible goods. The underlying concept is the same, but researchers encountering fungibiles in older sources — particularly translations of Roman law texts or nineteenth-century American treatises — should not treat it as a distinct doctrine from the modern fungible goods analysis. The distinction to watch is between fungibles and consumables (res fungibiles and res consumptibiles): things that are fungible are not necessarily consumed by use, though many fungibles are also consumables. Money is both; a library book is neither.
Core Elements
The classic civil law test for whether a thing qualifies as fungibiles asks:
1. Kind: Does the item belong to a category defined by type or grade rather than individual identity?
2. Measure: Can it be counted, weighed, or measured to establish equivalence?
3. Replaceability: Would the parties to a transaction be indifferent as between one unit and another of the same kind and measure?
If all three are satisfied, the thing is fungible. If any one fails — particularly if the parties have identified or designated a specific item — the thing is treated as a specific or determinate thing, not a fungibiles.
Why It Matters in Research
The fungible/non-fungible distinction is not merely taxonomic — it controls legal outcomes in at least three important areas:
Bailment and loan: A mutuum (loan for consumption) is the characteristic transaction involving fungibiles. The borrower acquires ownership of the fungible goods and owes back equivalent goods, not the identical items. A commodatum (loan for use) involves non-fungibles, where the identical thing must be returned. Misidentifying the transaction type in historical sources can lead a researcher to apply the wrong body of law entirely.
Commingling and tracing: When fungible goods are mixed with a larger mass of identical goods — grain in a silo, money in a bank account — property law faces a tracing problem that does not arise with specific things. Courts resolving disputes over commingled fungibles apply different presumptions than those governing identified property. Researchers tracking ownership disputes in equity or bankruptcy should be alert to this distinction appearing under varying vocabulary in historical sources.
UCC and modern commercial law: The Uniform Commercial Code uses fungible goods as a defined category in Articles 1, 7, and 9, with consequences for perfection of security interests, warehouse receipts, and bulk transfers. Researchers moving between pre-UCC sources (which use Roman law vocabulary including fungibiles) and post-UCC sources must recognize the continuity of concept beneath the change in terminology.
Historical Dictionary Support
Bouvier's Law Dictionary gives the clearest American summary of the civil law concept: fungibiles are things that "replace and represent each other" because they function mutually — mutuá vice funguntur. Bouvier draws on Roman and civil law sources and gives grain and money as the standard examples, contrasting them with a particular horse as the canonical non-fungible. The entry is compact but accurate as far as it goes.
What Bouvier does not address is the legal consequence of fungibility in specific transactional contexts — the dictionary entry names the category without mapping its doctrinal implications. Researchers should not expect nineteenth-century dictionary entries on this term to carry them far into the law of commingling, secured transactions, or commercial paper; those applications require treatise-level sources.
The phrase "things of a kind, as distinguished from specific things" used by Bouvier anticipates the UCC's own language almost precisely, which confirms that the modern commercial law vocabulary is a direct inheritance of the civil law framework, not a departure from it.
Jurisdictional Note
The concept is functionally universal in common law jurisdictions, though the Latin term fungibiles appears almost exclusively in civil law scholarship and older American treatises. Louisiana, as a civil law jurisdiction, uses the terminology more directly. In UCC jurisdictions, the statutory definition in Article 1 governs for commercial law purposes; civil law vocabulary governs only in academic, historical, or specialized trust and property contexts.