The Collaborative International Dictionary of English v.0.48:

Gimbal \Gim"bal\ (g[i^]m"bal), or Gimbals \Gim"bals\
   (g[i^]m"balz), n. [See Gimmal, n.]
   A contrivance for permitting a body to incline freely in all
   directions, or for suspending anything, as a barometer,
   ship's compass, chronometer, etc., so that it will remain
   plumb, or level, when its support is tipped, as by the
   rolling of a ship. It consists of a ring in which the body
   can turn on an axis through a diameter of the ring, while the
   ring itself is so pivoted to its support that it can turn
   about a diameter at right angles to the first.
   [1913 Webster]

   Gimbal joint (Mach.), a universal joint embodying the
      principle of the gimbal.

   Gimbal ring, a single gimbal, as that by which the cockeye
      of the upper millstone is supported on the spindle.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gimbal
    n 1: an appliance that allows an object (such as a ship's
         compass) to remain horizontal even as its support tips