In legal terminology, a complaint is any formal legal document that sets out the facts and legal reasons that the filing party or parties believes are sufficient to support a claim against the party or parties against whom the claim is brought that entitles the plaintiff(s) to a remedy. For example, the Federal Rules of Civil Procedure (FRCP) that govern civil litigation in United States courts provide that a civil action is commenced with the filing or service of a pleading called a complaint. Civil court rules in states that have incorporated the Federal Rules of Civil Procedure use the same term for the same pleading.
