[Greek guros, a circle or ring.]
A gyroscope is a spinning device used as a navigational device in ships and aircraft (a gyrocompass) and as a way to keep an object stable (a gyrostabilizer). A rotating charged particle generates a magnetic field, a principle called gyromagnetism. A gyrocopter (formed on the model of helicopter) has an unpowered rotating wing. Someone practising the form of divination called gyromancy walked in a circle until they fell down from dizziness, the place in the circle at which they fell giving the required indication.