What term describes a party's statement or claim made in a court pleading?

The term that best describes a party's statement or claim made in a court pleading is "allegation." In legal contexts, an allegation refers specifically to a statement or claim, which one party asserts to be true, typically without yet providing proof. Allegations are foundational claims in legal pleadings that are subject to proof as the case progresses. They serve as the basis for the claims made in the case and are important in establishing the issues that the court will ultimately address.

While terms like "affirmation," "declaration," and "assertion" may relate to a person's stated position or belief, they do not carry the specific legal connotation that "allegation" does within the context of court pleadings. For example, an affirmation generally signifies a positive assertion that something is true, while a declaration is a broader term that can refer to a formal statement, often used in different legal contexts. An assertion, similarly, is a confident statement but lacks the formal nature associated with a legal claim. Therefore, "allegation" is the precise term used to denote a claim made by one party in a legal action that requires substantiation.