rejoinder

A rejoinder is a legal response given by the defendant to the plaintiff’s response in the pretrial phase of a civil lawsuit. Rejoinders allow the defendant to address any new points or issues raised by the plaintiff in their reply, ensuring that all arguments and defenses are fully presented before the court. 

Procedurally, the plaintiff files a complaint first, and then the defendant files an answer in response to the complaint. Subsequently, the plaintiff files a reply to the defendant’s answer, perhaps introducing new evidence or arguments, if the court allows. The defendant then could file a rejoinder addressing the new points raised by the plaintiff in their reply. While the Federal Rules of Civil Procedure (FRCP) does not explicitly mention a time frame for rejoinder filing, the deadline is usually set by the court at their discretion. If new points and issues are brought up in the rejoinder, the court could allow the plaintiff to file a surrejoinder to address these points.

Rejoinder is also a concept used in intellectual property (IP) litigation. In the context of IP litigation, restriction is the practice of requiring an applicant to elect a single invention for examination when an application discloses and claims multiple inventions. In this case, a rejoinder is the process of withdrawing a restriction requirement between an allowable elected invention and a nonelected invention when all claims to a nonelected invention depend on, or otherwise require, all the limitations of an allowable claim. Rejoined claims must still be fully examined. See the Manual of Patent Examining Procedure § 821.04 for more information.

To be eligible for rejoinder, a claim to a nonelected invention must depend on, or otherwise require, all the limitations of an allowable claim. Moreover, claims that do not require all the limitations of an allowable claim remain withdrawn from consideration. Rejoined claims fully comply with all requirements for patentability, including 35 USC 101, 102, 103, and 112. 

[Last reviewed in April of 2026 by the Wex Definitions Team] 

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