a wheel mounted in a set of rings so that its axis of rotation is free to turn in any direction: when the wheel is spun rapidly, it will keep the original direction of its rotation axis no matter which way the ring is turned: gyroscopes are used in gyrocompasses and to keep moving ships, airplanes, etc. level
Origin of gyroscopegyro- + -scope
A device consisting of a spinning mass, typically a disk or wheel, mounted on a base so that its axis can turn freely in one or more directions and thereby maintain its orientation regardless of any movement of the base.
- an apparatus composed of a wheel which spins inside of a frame (gimbal) and causes the balancing of the frame in any direction or position. In the form of a gyroscopic stabilizer, used to help keep aircraft and ships steady.
gyro- + -scope, from French coined in 1856 by physicist Leon Foucault, from Ancient Greek γῦρος (guros, “circle”) and σκοπός (skopos, “watcher”).