The term is also used in the realm of contracts to describe the joining of new parties to an existing agreement.
The rule allows claimants to consolidate all of their claims that they have against an individual who is already a party to the case.
[2] A party who sues for breach of contract can bring his suit for assault at a later date if he chooses.
Rule 20 of the Federal Rules of Civil Procedure addresses permissive joinder, which allows multiple plaintiffs to join in an action if each of their claims arises from the same transaction or occurrence, and if there is a common question of law or fact relating to all plaintiffs' claims.
For example, several landowners may join together in suing a factory for environmental runoff onto their property.
Courts have some discretion in determining what parties are indispensable, but the Federal Rules provide some guidelines.
There is a discretionary period after the initial filing, during which original pleadings may be amended as a matter of course.
Under Rule 42 of Federal Rules of Civil Procedure, the court, if actions involve a common question of law or fact, may join any or all issues or consolidate the actions or issue any other orders to avoid unnecessary cost or delay.
Cases may be joined "on account of the connection between them" by the President of the Court after hearing the Judge-Rapporteur and the Advocate General, and (except in national cases requesting a preliminary ruling), after also hearing the parties.