Definition
A Latin term meaning "a certain person" or "somebody"—used in legal contexts to denote an individual whose name is unknown or unspecified. In practice, quidam functions as a placeholder designation for an unidentified party, equivalent to "a certain person" or "a person unknown." The term appears most commonly in civil law traditions and in French legal usage, where identifying a party by name is impossible or not yet established at the time of pleading or proceeding.
Common Language
Modern common usage (Wiktionary): A nobody; a person of no importance.
Historical common usage (Webster's 1913): Somebody; one unknown.
The gap between common and legal meaning runs in opposite directions depending on the era. Modern common usage has drifted toward a dismissive sense—a quidam is a nonentity, someone beneath notice. The legal meaning carries no such connotation. In law, quidam is strictly neutral: the person may be entirely significant to the proceeding; their name simply is not known. A researcher encountering quidam in a legal source should not import the modern derogatory sense.
Common Confusion
Quidam is occasionally confused with John Doe or its civil law equivalents (Durand in French practice, Nomen Nescio in Latin documents). The functional role is similar—all designate an unidentified person—but quidam is the Latin term proper, while John Doe is a common law fixture with its own distinct procedural history. In French civil law sources, quidam and the French vernacular usage overlap almost completely; in English common law sources, the term is rarer and typically signals a civil law influence or a learned Latin reference.
Why It Matters in Research
Quidam is a low-frequency term in English common law sources but appears with greater regularity in civil law treatises, French legal texts translated into English, and in mixed-jurisdiction materials from Louisiana and Quebec. Researchers working in those corpora should treat quidam as a functional equivalent to "person unknown" rather than a term of art with distinct procedural consequences.
Two navigational traps deserve attention. First, the appearance of quidam in an English-language legal source often signals that the author is drawing on civilian sources or continental learning—its presence can help date or situate a text within a particular intellectual tradition. Second, the Black's Law Dictionary entries for quidam append the maxim Quidquid enim sine dolo et culpa venditoris accidit in eo venditor securus est ("For concerning anything which occurs without deceit and fault on the part of the vendor, the vendor is secure") without clearly marking it as a separate entry. The maxim is a vendor liability principle from Roman sales law and has no direct connection to the procedural meaning of quidam as an unidentified person. This editorial adjacency in historical dictionaries has caused occasional confusion; the two should be treated as unrelated entries that happen to share a Lat. header abbreviation.
Researchers should also note that quidam does not appear with any meaningful frequency in American case law outside of Louisiana, and even there it is largely confined to older materials predating codification of modern pleading rules.
Historical Dictionary Support
Both the first and second editions of Black's Law Dictionary give identical definitions: "Somebody. This term is used in the French law to designate a person whose name is not known." The second edition adds a citation to Brown v. Bellows, 4 Pick. (Mass.) 198, which is attached not to quidam itself but to the vendor liability maxim that follows. This citation placement has caused ambiguity in subsequent references.
The historical dictionaries are consistent with each other and accurate as far as they go, but they are thin. Neither edition explains why an English-language legal dictionary would define a term primarily by reference to French law, nor do they address whether quidam carried any procedural significance in American or English practice. The entry functions more as a glossary note than a working definition. Researchers should not expect historical dictionaries to resolve questions about the term's procedural effect; those answers must be sought in civilian treatises and French legal sources directly.
Webster's 1913 confirms the general-language meaning ("somebody; one unknown") with a reference to Spenser, establishing that the word was absorbed into literary English without acquiring any common-law technical meaning.
Jurisdictional Note
Quidam is primarily a civil law term and carries the most practical significance in Louisiana, Quebec, and sources drawing on French legal practice. In English common law jurisdictions, it is almost entirely a learned Latin reference with no procedural standing independent of whatever the author chose to attach to it.