What is a claim made by a defendant in a civil lawsuit against the plaintiff called?

In a civil lawsuit, when a defendant makes a claim against the plaintiff, it is termed a counterclaim. This legal mechanism allows the defendant to assert their own claims and seek relief, effectively turning the tables on the plaintiff within the same legal proceeding. The counterclaim is filed in response to the plaintiff's original complaint and is governed by the same set of rules that apply to the initial claim.

This feature of civil procedure serves to promote judicial efficiency by allowing the court to resolve all disputes between the parties in a single action, rather than requiring separate lawsuits for different claims. The incorporation of a counterclaim can lead to a more comprehensive resolution of the issues at stake between the parties.

In contrast, other terms presented in the question describe different aspects of civil litigation. A cross-claim refers to a claim brought by one defendant against another defendant or by one plaintiff against another plaintiff in the same action. A claimant's complaint is the initial pleading that sets forth the plaintiff's claims against a defendant. An affirmative defense is a legal defense raised by the defendant to negate liability, which does not assert a claim against the plaintiff but rather provides a reason the defendant should not be held liable. Thus, the proper label for a defendant's claim against a plaintiff is