(civil law) the first pleading of the plaintiff setting out the facts on which the claim for relief is based WordNet 3.0 & Open English WordNet

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 to a remedy. Wikipedia

A type of legal document Wikipedia Disambiguation

Legal document, the filing of which initiates a lawsuit Wikidata

In a civil action, the first pleading of the plaintiff setting out the facts on which the claim is based; The purpose is to give notice to the adversary of the nature and basis of the claim asserted. Wiktionary