PLAINTIFFS - The Law Mind Legal Dictionary

PLAINTIFFSAuthored

The Law Mind • 1287 words

Definition

The plural of plaintiff: the parties who initiate a civil action by filing a complaint or petition against one or more defendants. Plaintiffs assert that they have suffered a legal wrong or injury entitling them to relief — whether damages, injunctive relief, a declaratory judgment, or some other remedy the court can provide.

In equity proceedings, plaintiffs are traditionally styled complainants or petitioners, though modern merged civil procedure systems use plaintiff across the board. The substantive requirements for who may serve as a plaintiff, and how multiple plaintiffs may be joined in a single action, vary by procedural context.

Where multiple parties bring suit together, each must independently satisfy standing requirements and, in federal court, constitutional injury-in-fact analysis. Their claims need not be identical, but they must share a sufficient legal or factual nexus to warrant joinder under the applicable rules.

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Common Confusion

PLAINTIFFS vs. CLAIMANTS vs. PETITIONERS vs. COMPLAINANTS: These terms all describe parties who initiate or advance a legal proceeding, but context controls the label. Petitioner typically appears in appellate proceedings, administrative hearings, and family law matters. Complainant is the traditional equity term and survives in some states and in administrative law. Claimant is common in insurance, workers' compensation, and claims-specific proceedings. Researchers working across time periods and jurisdictions will encounter all four labels for what is functionally the same role. Conflating them when searching historical sources or indexing material is a common source of missed results.

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Core Elements

For multiple parties to join as co-plaintiffs, classical doctrine required satisfaction of three conditions, reflected in Bouvier's synthesis of the case law:

1. Unity of interest in the subject matter. Co-plaintiffs must share a common stake in what is at issue, not merely parallel or related grievances. Courts denied joinder where plaintiffs' interests were legally distinct even if factually related.

2. Unity of object. The parties must seek the same general relief or outcome — not different remedies arising from different legal theories running to different plaintiffs alone.

3. Entitlement to relief. Each party joined as a plaintiff must independently be entitled to the relief sought. A party who cannot state a claim does not gain standing by joining with one who can.

Modern joinder rules under Federal Rule of Civil Procedure 20 liberalized these requirements, permitting joinder when claims arise out of the same transaction or occurrence and share a common question of law or fact. Historical sources applying the stricter unity tests will not map cleanly onto modern joinder analysis.

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Why It Matters in Research

The term plaintiffs is deceptively simple — it is the plural of a foundational procedural concept — but several research traps deserve attention.

First, the equity/law divide. Historical sources consistently treat plaintiffs at law and complainants in equity as distinct procedural categories with different rules governing who may sue, how claims may be joined, and what disabilities applied. Bouvier addresses each track separately. Researchers working with pre-merger materials (pre-1938 federally; varying dates by state) must attend to which track a case arose in, because the rules governing who could sue, and how multiple parties could be joined, were not the same.

Second, joinder law evolved substantially. The classical unity-of-interest test Bouvier describes gave way to the more permissive transactional test in modern civil procedure. A precedent applying the classical test to deny multi-plaintiff joinder may be of limited value in predicting modern outcomes, but remains essential for understanding historical case outcomes.

Third, capacity and disability rules. Bouvier flags that certain parties faced absolute or partial disabilities preventing suit: alien enemies, persons lacking legal capacity, parties with only equitable (not legal) title suing at law, and parties holding interests in different capacities. These disabilities do not always appear on the face of historical opinions. Researchers analyzing pre-20th century litigation must independently verify whether a plaintiff's capacity to sue was restricted under the law of that time and jurisdiction.

Fourth, standing doctrine. Modern federal plaintiffs face constitutional standing requirements (injury in fact, causation, redressability) that have no direct historical counterpart. When the corpus references plaintiff-related dismissals, researchers should confirm whether the dismissal sounds in classical capacity/joinder doctrine or modern constitutional standing — the two are frequently confused in secondary literature.

Fifth, class actions. When the corpus references named plaintiffs in class contexts, the term carries a specific procedural meaning (class representative or lead plaintiff) that differs from ordinary plaintiff status. Research into class action materials requires attention to whether a plaintiff appears individually, representatively, or both.

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Historical Dictionary Support

Bouvier's treatment of plaintiffs spans three distinct frameworks: multi-party joinder in equity, capacity to sue generally, and the rules governing actions at law on contracts.

On joinder, Bouvier synthesizes a body of case law requiring unity of interest and unity of object, drawing on chancery and state equity decisions. The restrictions were real and frequently litigated: courts turned away co-plaintiffs whose claims arose under different contracts or whose interests were vested in them in different capacities. Bouvier notes that persons representing antagonistic interests cannot be joined as complainants — a rule that modern practitioners would recognize as a conflict-of-interest principle but that historically operated as a joinder bar.

On capacity, Bouvier draws a useful distinction between absolute disabilities (which prevented suit entirely during their continuance) and partial disabilities (which prevented suit alone, but not with a proper party). The treatment of alien enemies reflects wartime common law doctrine; the treatment of equitable title reflects the law/equity split that shaped who could sue where.

On contract actions at law, Bouvier states the classical rule clearly: the action must be brought in the name of the party in whom the legal interest is vested. This explains why many historical contract cases appear to have only one plaintiff even when multiple parties had an economic stake — the legal interest holder sued, and others who had equitable interests could seek relief in chancery.

What Bouvier does not address: modern constitutional standing, the class action mechanism, statutory plaintiff-creation (where a statute confers a right of action on a defined class), or the merged civil procedure landscape. For anything post-1938 federally, or post-merger by state, Bouvier's procedural guidance is historical context, not operational doctrine.

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Jurisdictional Note

State court systems vary in how they label and regulate the plaintiff role. Some states retain complainant or petitioner terminology in specific proceedings even under merged procedure rules. Joinder requirements for multiple plaintiffs also vary: some states follow the federal transactional test closely; others retain older unity-based formulations in their rules or case law. Researchers should not assume that federal joinder doctrine, or Bouvier's classical synthesis, governs in a particular state court without verification.

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Encyclopedia Cross-Reference

The Law Mind Torts & Personal Injury Encyclopedia: Negligence — Eggshell Plaintiff / Thin Skull Rule (the plaintiff's pre-existing condition and how it affects damages analysis); Defamation — Private Plaintiffs and State Standards (the distinction between public figures and private plaintiffs and the constitutional standards that govern each).

The Law Mind Remedies & Equity Encyclopedia: Unclean Hands — Inequitable Conduct by the Plaintiff Barring Equitable Relief (the doctrine by which a plaintiff's own misconduct may defeat an otherwise valid claim for equitable relief).

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PLAINTIFFSmain

Bouvier's Law Dictionary • 1928

All persons having a unity of interest in the subject-matter; 3 Barb. Ch. 397; 2 Ala. N. S. 209; and in the object to be attained; 2 Ia. 55; 118 Mo. 348; 89 Va. 455: who are entitled to relief: 14 Ala. N. S. 135; may join as plaintiffs. The rights claimed must not arise under differ ent contracts: 8 Pet. 123; 5 J. J. Marsh. 154; or be vested in the same person in different capacities; 1 Busb. Eq. 196. And see 1 Paige 637; 5 Metc. 118. Persons representing antagonistic interests cannot be joined as complainants; 14 So. Rep. (Ala.) 765. Assignor and assignee. The assignor of a contract for the sale of lands should be joined in a suit by the assignee for specific performance; 3 Sandf. Ch. 614; and the assignor of part of his interest in a patent in a suit by assignee for violation; 3 Mc- Lean 350. But he should not be joined where he has parted with all his legal and beneficial in- terest; 32 Me. 203, 343; 13 B. Monr. 210. The assignee of a mere chose in action may sue in his own name, in equity; 17 How. 43; 5 Wisc. 270; 6 B. Monr. 540; 7 id. 273. Corporations. Two or more may join if their interest is joint; 8 Ves. 706. A cor- poration may join with its individual mem- bers to establish an exemption on their behalf; 8 Anstr. 738. Corporations them- selves are indispensable parties to a bill which affects their corporate rights or lia- bilities: 148 U. S. 603. Husband and wife must join where the husband asserts an interest in behalf of his wife; 6 B. Monr. 514; 3 Hayw. 252; 5 Johns. Ch. 196; 9 Ala. 133; as, for a legacy; 5 Johns. Ch. 196; or for property devised or descended to her during covert- ure; 5 J. J. Marsh. 179, 600; or where he applies for an injunction to restrain a suit at law against both, affecting her interest; 1 Barb. Ch. 813. Where a widow sues to set aside a deed executed by herself and hus- band on the ground that it was procured by fraud, the administrator of the husband is not a necessary party; 58 Hun 605. Under modern statutes for the enlarge- ment of the rights and remedies of married women, it is in many cases unnecessary to join the husband in suits to which he was formerly a necessary party. See MARRIED

PLAINTIFFSmain

Bouvier's Law Dictionary • 1928

In general, all persons, whether natural or artificial, may sue in equity; and an equitable title only is suf- ficient; 10 Ill. 332. Incapacities which prevent suit are absolute, which disable during their continuance, or partial which disable the party to sue alone. Persons representing antagonistic in- terests cannot be joined as complainants; 14 So. Rep. (Ala.) 765. Alien enemies are under an absolute in- capacity to sue. Alien friends may sue; Mitf. Eq. Pl. 129; if the subject-matter be not such as to disable them; Co. Litt. 129 b; although a sovereign; 1 Sim. 94; 8 Wheat. 464; 4 Johns. Ch. 370; Ad. Eq. 314. In such case he must have been first recog- nized by the executive of the forum; Story, Eq. Pl. § 55; 3 Wheat. 324. In such case the sovereign submits to the jurisdiction, as to the subject-matter, and must answer on oath; Mitf. Eq. Pl. 30; Ad. Eq. 313; 6 Beav. 1. See SOVEREIGN. Attorney-general. Government (in Eng- land, the crown) may sue both in its own behalf, for its own political rights and in- terests, and in behalf of the rights and in- terests of those partaking of its prerogatives or claiming its peculiar protection; Mitf. Eq. Pl. 421; Coop. Eq. Pl. 21, 101; usually by the agency of the attorney-general or solicitor-general; Mitf. Eq. Pl. 7; Ad. Eq. 312. See INJUNCTION; QUO WARRANTO; MANDAMUS; TRUSTS. Corporations, like natural persons, may sue; Moraw. Pr. Corp. § 357; Grant, Corp. 198; although foreign; id. 200; but in such case the incorporation must be set forth; 1 Cr. M. & R. 296; 4 Johns. Ch. 327; as it must if they are domestic and created by a private act; 3 Conn. 199; 15 Viner, Abr. 198. All the members of a voluntary association must be joined; 15 III. 251; unless too numerous; 2 Pet. 566; 3 Barb. Ch. 362. See JURISDICTION; EXPRESS COM-

PLAINTIFFSmain

Bouvier's Law Dictionary • 1928

In general, all persons who have a just cause of action may sue, unless some disability be shown; Dicey, Part. 1. An action on a contract, of whatever des- cription, must be brought in the name of the party in whom the legal interest is vested; 3 B. & P. 147; 5 S. & R. 27; 10 Mass. 230, 287; 1 Pet. C. C. 109; 2 Root 119; 21 Wend. 110. See 51 N. H. 71. On simple contracts, by the party from whom (in part, at least) the consideration moved; 1 Stra. 592; 2 W. & S. 237; although the promise was made to another, if for his benefit; 3 Pick. 83; 10 Wend. 87, 156; 5 Dana 45; and not by a stranger to the consideration, even though the contract be for his sole benefit; Browne, Act. 101. On contracts under seal, by parties to the instrument only; 10 Wend. 87; Co. Litt. 231. Agents contracting in their own name, without disclosing their principals, may, in general, sue in their own names; 3 B. & Ald. 280; 5 M. & W. 650; 5 Pa. 41; or the principals may sue; 6 Cow. 181; 3 Hill N. Y. 72; 2 Ashm. 485; Broom, Part. 44. See, generally, Ans. Contr. 352. So they may sue on contracts made for an unknown principal; 3 E. L. & E. 391; and also when acting under a del credere commission; 4 Maule & S. 566; 10 Barb. 202; but not an ordinary merchandise broker. An auctioneer may sue for the price of goods sold; 1 H. Bla. 81; 16 Johns. 1; but a mere attorney having no beneficial interest may not sue in his own name; 10 Johns. 388. Alien enemies, unless resident under a license, or contracting under specific license, cannot sue, nor can suit be brought for their benefit; 1 Campb. 482; 1 Kent 67; 11 Johns. 418. License is presumed if they are not ordered away; 10 Johns. 69; 6 Binn. 241. See, also, Co. Litt. 129 6; 15 East 260; 1 Kent 68. Alien friends may bring actions concern- ing personal property; Bac. Abr. Aliens; for libel published here; 8 Scott 182; and now, in regard to real estate generally, by statute; 12 Wend. 342; see 15 Tex. 495; and, by common law, till office found, against an intruder; 1 Johns. Cas. 399. But see 5 Cal. 373. See WAR. Asa general rule, an alien may maintain a personal action in the federal courts; 8 Story 458; 4 McLean 516. Assignees of choses in action cannot, at common law, maintain actions in their own names; Broom, Part. 10; 42 Me. 221. Promissory notes, bills of exchange, bail- bonds, and replevin bonds, etc., are excep- tions to this rule; Hamm. Part. 108. As- signees of a note and mortgage can main- tain an action thereon, whether they paid any consideration for the assignment, or not; 74 Wis. 289. An assignee of real estate may have an action in his own name for breaches of a covenant running with the land, occurring after assignment; 14 Johns. 89; and he need not be named in an express covenant of this character; Broom, Part. 8. An assignee in insolvency or bankruptcy should sue in his own name on a contract made before the act of bankruptcy or the

plaintiffsnoun

Wiktionary (English) • 2026

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plural of plaintiff

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