Civil Procedure
Joinder
The procedural rules for adding claims or parties to a lawsuit so related disputes can be handled together.
Governing rule: Fed. R. Civ. P. 18-21
Plain-English definition
Joinder is the umbrella concept for combining parties and claims in one case. The rules try to balance efficiency against fairness: related disputes should often be resolved together, but unrelated parties should not be dragged into a case just because it is convenient.
How it works
Joinder questions arise in complaints, amended complaints, counterclaims, crossclaims, third-party complaints, intervention motions, and class actions.
Why it matters
Joinder affects case size, discovery burden, jurisdiction, venue, and settlement complexity.
Related terms
Consolidation
Combining related cases for coordinated management, discovery, hearings, or trial.
Intervention
A procedure allowing a nonparty to join an existing lawsuit because the case may affect its interests.
Severance
Separating claims or parties into different proceedings to avoid unfairness, confusion, or inefficiency.
More in Civil Procedure
Amended Complaint
A revised complaint that changes, adds, or clarifies allegations, parties, or claims after the original complaint was filed.
Answer
The defendant's formal written response to the plaintiff's complaint, admitting or denying each allegation.
Class Certification
The judicial decision to allow a lawsuit to proceed as a class action on behalf of similarly-situated plaintiffs.
Collateral Estoppel
Also called issue preclusion. The doctrine that prevents re-litigating a specific issue that was actually decided in a prior case.
Complaint
The initial pleading filed by the plaintiff that starts a civil lawsuit.
Consolidation
Combining related cases for coordinated management, discovery, hearings, or trial.
Counterclaim
A claim brought by a defendant against the plaintiff within the same lawsuit.
Crossclaim
A claim by one party against a co-party, such as one defendant suing another defendant in the same case.
Not legal advice. Definitions are for general reference. Consult an attorney before relying on any term in a real case.