The federal courts of appeal are formally called the US Court of Appeals Circuit Courts. Most cases are reviewed by a panel of three judges, although important cases may occasionally be heard "en...
To use a federal court the party suing must have "standing," meaning they have to have both a reason to sue and the right to use a federal court. To have a reason to sue means you have to have a...
Trial courts hear both criminal and civil trials of ALL types. Think of any violation of a either a civil or a criminal law and (in the US) you can demand a jury trial for it.