In law, an appeal is a process for making a formal challenge to an official decision. Depending on circumstances, appeals may be made to the same authority or to a higher judicial authority. In common law jurisdictions, most commonly, this means formally filing a notice of appeal with a lower court, indicating one's intention to take the matter to the next higher court with jurisdiction over the matter, and then actually filing the appeal with the appropriate appellate court.
An appellate court is a court that hears cases, in which a lower court — either a trial court or a lower-level appellate court — has already made a decision, but in which at least one party to the action wants to challenge this ruling based upon some legal grounds that are allowed to be appealed either by right or by leave of the appellate court. These grounds typically include errors of law, fact, or due process.
In different jurisdictions, appellate courts are also called appeals courts, courts of appeals, superior courts, or supreme courts.
Who can appeal
A party who files an appeal is called an appellant or petitioner, and a party on the other side is an appellee or respondent. Cross-appeals can also occur, when more than one party to a case is unhappy with the decision in some way, often when the winning party claims that more damages were deserved than were awarded.
The appellant is the party who, having lost part or all their claim in a lower court decision, is appealing to a higher court to have their case reconsidered. This is usually done on the basis that the lower court judge erred in the application of law, but it may also be possible to appeal on the basis of court misconduct, or that a finding of fact was entirely unreasonable to make on the evidence.
The appellant in the new case can be either the plaintiff (or claimant), defendant, or respondent (appellee) from the lower case, depending on who was the losing party. The winning party from the lower court, however, is now the respondent. In unusual cases the appellant can be the victor in the court below, but still appeal.
An appellee is the party to an appeal in which the lower court judgment was in its favor. The appellee is required to respond to the petition, oral arguments, and legal briefs of the appellant. In general, the appellee takes the procedural posture that the lower court's decision should be affirmed.