A panel is a thing that blocks one area from another. It is usually made up of thin sheet metal.
A panel may be a flat or sculptured area that is part of a larger structure such as a piece of furniture or one element of a multi-panel screen.
A panel is a committee or jury used to decide some matter. In a legal context it may refer to a subset of a full set of appeal court judges, in contrast to an En banc hearing, which involves them all. In accident investigations, a full investigation may involve sub-panels with expertise in differing areas, in the aircraft context perhaps covering avionics, structures, engines and so on.
A control panel is a flat area containing controls and indicators. Commonly found in aircraft but may be associated with the operation of any machinery.
