About appeals; an appellate court has the power to review the judgment of a lower court (trial court) or tribunal. For example, the U.S. circuit courts of appeals review the decisions of the U.S. district courts.
Source: U.S. Courts
Having to do with appeals. An appellate court can review a lower courts (called a "trial court" or "superior court") decision. For example, California Courts of Appeal review the decisions of the superior courts.
Source: California Courts.