Plain English Meaning

Flying the airplane by reading the instruments instead of looking out the window. The pilot sets the nose attitude and wing angle using what the instruments show, then adds the right power to get the speed, climb, or descent they want.

Full Definition

A method of controlling an aircraft solely by reference to the flight instruments, in which the pilot establishes and maintains the desired pitch and bank by interpreting the instrument indications rather than by looking outside. Power and trim are then adjusted to achieve the desired performance for each phase of flight.