Definition
To bring a party into a legal proceeding by due course of law; to sue or prosecute in a court. In modern American procedural practice, the term carries a more specific meaning: to bring a third party into an existing lawsuit, typically by a defendant who seeks to shift or share liability with someone not yet named in the action. This third-party practice is now codified in the Federal Rules of Civil Procedure and their state equivalents.
Two uses of the term coexist in legal literature and must be distinguished by era and context:
1. Classical/common law usage: To sue or prosecute generally — to institute a legal action against another party. This is the sense captured in all historical dictionaries and remains embedded in archaic pleading forms and records.
2. Modern procedural usage: To bring a third party into pending litigation — specifically, for a defendant to assert a claim against a non-party who may be liable to the defendant for all or part of the plaintiff's claim. Under Federal Rule of Civil Procedure 14, this is called third-party practice; "implead" is the operative verb in that context.
Common Language
Modern common usage (Wiktionary): To sue in court; raise an action against a defendant.
Historical common usage (Webster's 1913): To institute and prosecute a suit against, in court; to sue or prosecute at law; hence, to accuse; to impeach.
Both the common and historical lay definitions track the older legal meaning — general prosecution by legal process — and stop there. Neither captures the procedurally precise modern sense: bringing in a stranger to existing litigation to answer a derivative or contribution claim. A researcher reading "impleaded" in a modern brief or federal motion should understand it refers to third-party joinder, not merely to being sued.
Common Confusion
IMPLEAD vs. INTERPLEAD: These terms are phonetically similar and appear in the same procedural contexts, causing persistent confusion. Interpleader is a distinct remedy: a stakeholder holding property claimed by two or more parties forces those claimants to litigate the claim among themselves. Impleading brings in a third party to answer a derivative liability claim. The mechanics, purposes, and governing rules are different. See INTERPLEADER.
IMPLEAD vs. JOIN: Joinder is the broader procedural concept encompassing all methods of adding parties or claims. Impleading is one specific joinder mechanism — third-party practice by a defending party. A plaintiff does not implead; a plaintiff joins or adds parties under different procedural rules.
Why It Matters in Research
The term does real work in two very different procedural universes, and conflating them produces research errors.
In historical sources — cases, treatises, and records predating the Federal Rules (pre-1938) — "impleaded" simply means "sued." Court records will describe a defendant as "impleaded by" the plaintiff, which is formulaic language meaning nothing more than that an action was commenced. Burrill notes the word was "still used in records" even in his era, suggesting it was already becoming archaic in ordinary usage while surviving in formal pleading. Researchers reading 19th-century decisions must resist importing the modern third-party meaning backward.
In modern sources — federal and state procedural rules, contemporary litigation documents — "implead" almost always refers to Rule 14-style third-party practice. The defendant-turned-third-party-plaintiff impleads a third-party defendant who may owe indemnification or contribution. This is a creature of the merged procedural system that did not exist in the common law forms of action.
Cross-corpus alert: Equity practice developed its own mechanisms for drawing in absent parties, and some older chancery materials use "implead" loosely to cover those procedures. Be cautious when the source is an equity court — the procedural mechanism described may not map onto either the classical or modern third-party sense.
Jurisdictional variation matters here. Many states follow FRCP Rule 14 closely, but some retain older terminology or impose different timing and leave requirements for third-party complaints. State practice guides are essential before assuming federal doctrine applies.
Historical Dictionary Support
The historical dictionaries are unanimous on the classical definition and say nothing more: to sue or prosecute by due course of law. Black's (both editions), Bouvier's, Burrill's, and Rapalje & Lawrence all reproduce essentially the same formulation, tracing to Termes de la Ley, a foundational glossary of legal French terms. This consensus reflects the term's origins in Law French (impleder, empleder) and Latin (implacitare), where it simply meant to bring a plea against someone.
What the historical sources do not address — because it did not yet exist in recognizable form — is the modern third-party procedural sense. Anderson's Dictionary of Law unhelpfully cross-references only "PLEA," offering no independent definition. Burrill alone notes the term's continued presence in records, a useful reminder that survival in formal documents does not indicate vitality in practice.
The historical dictionaries are consistent but thin. Researchers should not expect them to illuminate the modern procedural meaning; for that, the Federal Rules, advisory committee notes, and Wright & Miller's Federal Practice and Procedure are the appropriate sources.
Jurisdictional Note
Federal practice governs third-party impleader under FRCP Rule 14, which requires leave of court if the third-party complaint is filed more than 14 days after the original answer. State courts vary: some follow Rule 14 closely, others impose stricter leave requirements, different timing windows, or limit the claims that may be asserted against a third-party defendant. Researchers working in state court should not assume federal third-party practice doctrine controls.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Third-Party Practice; Joinder of Parties; Pleading (Historical Forms).