What is a counterclaim?

A counterclaim is indeed defined as a claim made by a defendant against a plaintiff in a legal action. This legal concept allows the defendant to assert their own claims in response to the original claims made by the plaintiff. Essentially, it is a way for the defendant to turn the tables and seek relief or damages from the plaintiff within the same lawsuit. This can help address any grievances the defendant may have and can also lead to a more comprehensive resolution of the entire dispute during the court proceedings.

In the context of the given options, the other choices represent different legal concepts. For instance, a claim made by the plaintiff in a lawsuit does not reflect the defendant's perspective, while a formal request to dismiss a case pertains to wanting to invalidate the entire case rather than responding to it. Lastly, a failure to respond within a designated time refers to a lack of action rather than an affirmative claim made in response to the plaintiff. Thus, the distinction of a counterclaim as the defendant's proactive measure illustrates its unique role in litigation.