Plain English Meaning

Using the throttle and the controls together so the aircraft is going at the right speed and producing the right amount of power for whatever you are trying to do at that moment.

Full Definition

The coordinated control of engine power setting and airspeed to achieve a desired flight condition, such as climb, cruise, descent, approach, or landing. It involves selecting the correct power output and adjusting pitch attitude so the aircraft maintains the airspeed appropriate to the phase of flight and the being flown.