GIMBAL  , a

mechanical device for hanging some object so that it should keep a horizontal and constant position, while the body from which it is suspended is in free motion, so that the motion of the supporting body is not communicated to it . It is thus used particularly for the suspension of compasses or chronometers and lamps at sea, and usually consists of a ring freely moving on an axis, within which the object swings on an axis at right angles to the ring . The word is derived from the O . Fr. gemel, from Lat. gemellus, diminutive of geminus, a twin, and appears also in gimmel or jimbel and as gemel, especially as a term for a ring formed of two hoops linked together and capable of separation, used in the 16th and 17th centuries as betrothal and keepsake rings . They sometimes were made of three or more hoops linked together .