• gyro compass, gyrocompass
    An instrument receiving its directive force from a gyroscope operated by electric motors. Its directive action is based on the mechanical laws governing the dynamics of rotating bodies. It consists of a heavy disc mounted in gimbals with a free suspension and driven at high speed by electrical power. A connected dial has the points and diagram of the mariner's compass marked on its face and from it is indicated the ship's true course. The force of a gyrocompass is maximum at the equator and absent at the poles.