A more thorough explanation:

An appeal is a legal challenge to a previous decision made by a court or administrative agency. The appeal is directed towards a higher legal power than the one that made the original decision. The person who initiates the appeal is called the appellant, while the person defending the original decision is called the appellee or respondent.

Appeals can be either of right or discretionary. An appeal of right is one that the higher court must hear if the losing party demands it, while a discretionary appeal is one that the higher court may, but does not have to, consider.

For example, if a person is found guilty in a trial court, they can appeal the decision to an appellate court. If the appellate court upholds the decision, the person can then appeal to a court of last resort, such as the United States Supreme Court. However, the Supreme Court does not have to hear the case if they do not want to.

Appeals can also be made in administrative law. For example, if a person disagrees with a decision made by an executive agency, they can appeal the decision in court.

Overall, an appeal is a way for a person to challenge a legal decision and seek a higher authority to review the decision.