Federal Aviation Administration FAR Part 1 Defintions
Federal Aviation Regulation  DEFINITIONS AND ABBREVIATIONS
General definitions. 
Administrator means the Federal Aviation Administrator or any person to whom he has delegated his authority in the matter concerned.
Aerodynamic coefficients means non-dimensional coefficients for aerodynamic forces and moments.
Air carrier means a person who undertakes directly by lease, or other arrangement, to engage in air transportation.
Air commerce means interstate, overseas, or foreign air commerce or the transportation of mail by aircraft or any operation or navigation of aircraft within the limits of any Federal airway or any operation or navigation of aircraft which directly affects, or which may endanger safety in, interstate, overseas, or foreign air commerce.
Aircraft means a device that is used or intended to be used for flight in the air.
Aircraft engine means an engine that is used or intended to be used for propelling aircraft. It includes turbosuperchargers, appurtenances, and accessories necessary for its functioning, but does not include propellers.
Airframe means the fuselage, booms, nacelles, cowlings, fairings, airfoil surfaces (including rotors but excluding propellers and rotating airfoils of engines), and landing gear of an aircraft and their accessories and controls.
Airplane means an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings.
Airport means an area of land or water that is used or intended to be used for the landing and takeoff of aircraft, and includes its buildings and facilities, if any.
Airship means an engine-driven lighter-than-air aircraft that can be steered.
Air traffic means aircraft operating in the air or on an airport surface, exclusive of loading ramps and parking areas.
Air traffic clearance means an authorization by air traffic control, for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace.