An appellate court is a court with the authority to review decisions made by lower courts, and to hand down new decisions, when appropriate. In most countries, the legal system has several levels, which allows people to potentially petition a series of appellate courts if they feel that their cases have not been judged fairly. One well-known example of this type of court is the Supreme Court of the United States, which is considered to be a court of last resort. Once a decision is handed down by the Supreme Court, there is no higher court of appeals.
The appellate system ensures that people who wish to appeal can do so. A wide variety of decisions can be appealed. Classically, people who are convicted of murder and sentenced to death typically appeal, with the goal of being found innocent, or at least to drag out the process to delay the carrying out of the sentence. Appeals are filed by a lawyer or team of lawyers, and experience with the appeals process is very helpful, as it can help to achieve the desired outcome.
Different appellate courts work differently, depending on the laws of their nations. In some cases, the court may only examine material from the trial, including testimony, presented evidence, speeches by the legal team, and the opinion of the judge in the case. As the appellate judges sift through the evidence, they are asked to decide whether or not the law was applied fairly in the case. In other instances, the court may hear new testimony and evidence.
In many cases, appellate court decisions are eagerly awaited. These decisions aren't just important for the people who filed the appeal; sometimes, an appellate court will be forced to set a legal precedent when they reach a decision. This precedent could in turn be used by lawyers and other judges, with the formal decision as filed being considered part of the body of case or judge made law. Because appellate decisions are used as a legal basis for arguments in future cases, they are typically meticulously written, designed to be as clear and defensible as possible.
You may also hear an appellate court called a court of appeals, and in some regions, these courts are referred to as “courts of errors,” referencing the idea that they are supposed to fix errors made by lower courts. The appellate system is broken up in a wide variety of ways, depending on the nation it is based in, so the next time you see an appellate court mentioned in the news, you might want to check and see which one it is; in the United States, for example, there are separate State and Federal appellate courts, with differing levels of authority.