Plain English Meaning

Cockpit instruments that work by spinning a small wheel inside them. Once the wheel is spinning fast, it stays steady in space, and the instrument uses that steadiness to show how the airplane is banking, pitching, turning, and which direction it's pointing.

Full Definition

A group of flight instruments that use a spinning rotor (a gyro) to sense and display the airplane's attitude, heading, and rate of turn. The three primary gyroscopic instruments in most general aviation airplanes are the attitude indicator, the heading indicator, and the turn coordinator (or turn-and-slip indicator). The are driven either by engine-supplied / or by electrical , depending on the airplane.