Definition
A relator is a private person at whose complaint or instigation a legal proceeding is brought in the name of the government or a public officer. The relator is not formally a party of record in the way a plaintiff is, but occupies a position analogous to a plaintiff: the action is brought on the relator's behalf, the relator typically bears the cost of prosecution, and the relator has a real interest in the outcome.
The term appears most commonly in two contexts:
1. Quo warranto proceedings. When the attorney general files an information in the nature of quo warranto — a proceeding to challenge someone's right to hold a public office or exercise a public franchise — the private individual who prompts the filing and in whose behalf it proceeds is the relator. The action is styled, in many jurisdictions, as "State ex rel. [Name] v. [Defendant]," meaning the state acts upon the relation of that named person.
2. Mandamus and other prerogative writs. A relator may similarly be the private party at whose instance a writ of mandamus or an attachment for contempt is sought, where the writ issues in the name of the court or sovereign rather than in the name of the private individual directly.
RELATRIX is the historical feminine form of the term, used when the relator was a woman.
Common Language
Modern common usage (Wiktionary): One who relates or tells; a narrator. Also, in mathematics, an expression of the identity element of a group used in a group presentation.
Historical common usage (Webster's 1913): One who relates; a relater or narrator. Also specifically: a private person at whose relation the attorney-general allows an information in the nature of a quo warranto to be filed.
The ordinary meaning — a teller or narrator — has essentially no legal content. The legal meaning carries a precise procedural weight: the relator is not merely someone who reports a grievance but a quasi-party who initiates and stands behind a government-name proceeding, often with corresponding rights and obligations that a mere informant would not have. Webster's 1913 captures both senses, which is why historical sources can be ambiguous when using the word loosely.
Common Confusion
Relator vs. informer: Rapalje & Lawrence treats "relator" as a synonym for "informer," and this overlap is understandable — both describe a private person who sets a proceeding in motion. But an informer in the penal-statute sense is typically anonymous and motivated by a statutory share of the penalty. A relator in the quo warranto or mandamus sense is a named party of record, known to the court and the defendant, and whose interest the proceeding is understood to vindicate. The procedural and reputational consequences differ significantly.
Relator vs. plaintiff: The relator is often described as "quasi the plaintiff," but the distinction matters. The attorney general (or equivalent public officer) controls the litigation in the government's name; the relator cannot unilaterally discontinue the action or bind the government on the merits. In practice, however, the relator typically funds the proceeding and may exercise substantial effective control.
Why It Matters in Research
Case caption signals: In historical and many current state court records, the presence of "ex rel." in a case style is the clearest indicator that a relator is involved. Searching for the relator's name alone may miss cases indexed under the government party; searching only the government party name will miss the relator's connection. Researchers must check both halves of the caption.
Scope variation over time: Bouvier notes that at strict common law, the relator was a creature of the Statute of Anne (9 Anne, c. 20), which formalized the relator's role in quo warranto proceedings. In American jurisdictions without a direct statutory analog, courts nevertheless allowed private-party-initiated informations, expanding the relator concept beyond its English statutory origins. Historical sources written before American procedural codes were consolidated may reflect the narrower English view.
Modern procedural displacement: In federal practice, the Federal Rules of Civil Procedure largely displaced the old prerogative writ framework. "Relator" in federal courts today appears most prominently in False Claims Act qui tam suits, where the private relator brings an action in the government's name to recover for fraud on the government. This is a distinct procedural creature from the common law quo warranto relator, though the structural logic — private party animating a government-name action — is the same. Researchers moving between historical and modern sources must recognize that "relator" in a contemporary federal context almost certainly means a qui tam plaintiff under the False Claims Act, not a quo warranto petitioner.
State variation in caption conventions: Some states style the proceeding "People ex rel." or "Commonwealth ex rel." rather than "State ex rel." Burrill and Black both write from a general common law perspective that papers over these state-by-state caption differences, which can create indexing challenges in historical court records.
Historical Dictionary Support
Black's (both editions) and Burrill agree on the core definition: the relator is the private person at whose instance a quo warranto information or mandamus is filed, quasi the plaintiff. Burrill adds the useful detail that the writs themselves are said to be prosecuted "ex relatione" — a Latin phrase that directly produces the "ex rel." shorthand in case captions.
Bouvier adds important historical texture, noting the English statutory origin and the American departure from strict English practice that allowed private-party informations even without a replicating statute. This is a meaningful divergence that Black's does not fully develop.
Rapalje & Lawrence's equation of relator with "informer" reflects the older, looser usage and is the least precise of the shelf definitions for research purposes. It captures the functional reality — the relator informs the court of the wrong — but obscures the relator's procedural distinctiveness.
The Bouvier entry retrieved under "Ex Tempore" and neighboring Latin phrases appears to be a retrieval error and contains no material relevant to relator.
None of the historical dictionaries address the False Claims Act qui tam relator, which is the dominant modern federal usage. This is the most significant gap in the shelf sources for contemporary researchers.
Jurisdictional Note
In federal court, "relator" now most commonly refers to the qui tam plaintiff under the False Claims Act (31 U.S.C. § 3730), a usage entirely absent from the historical dictionaries. State courts retain the quo warranto relator concept in varying procedural forms; some states have codified the relator's rights and obligations explicitly, while others continue to rely on common law practice.
Encyclopedia Cross-Reference
employment_95: Public Sector Labor Relations (The Law Mind Employment & Labor Law Encyclopedia) — relevant where quo warranto or mandamus proceedings arise in public employment and office contexts.