The term is particularly used by the United States Federal Aviation Administration for classification purposes. Powered-lift is one of the seven categories of aircraft designated by the Federal Aviation Administration; the other six being Airplane, Rotorcraft, Glider, Lighter-Than-Air, Powered parachute, and Weight-shift control.
Powered-lift means a heavier-than-air aircraft capable of vertical takeoff, vertical landing, and low speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on nonrotating airfoil(s) for lift during horizontal flight.
A convertiplane is an aircraft which uses rotor power for vertical takeoff and landing (VTOL) and converts to fixed-wing lift in normal flight.
In tiltrotor and tiltwing designs such as the Bell Boeing V-22 Osprey, the rotor swings forward to act as a propeller in forward flight. Some designs have a ducted rotor design, in which the rotor is surrounded by a large ring-shaped duct to reduce tip losses.