That formal court documents in which a litigant formally sets out the facts and legal arguments which support that the person's position.
Depending on the nature of the claim, this can be either the Petition or the set of a statement of claim and a statement of defence.
Pleadings can be in writing or they can exceptionally be made verbally to a court, during a hearing.
Pleadings are essential to the trial or hearing process as they set out the parameters of what - exactly - a litigant is asking the Court for. The Court is neutral and cannot invent, create or carve relief from the facts or coach a litigant in regards to evidence required to obtain certain relief. The pleadings must provide the Court with a litigant's road map; what they want (relief claimed) and why they want it (facts in support).