Source : Webster's Revised Unabridged Dictionary (1913)

Hanging \Hang"ing\, a.
   1. Requiring, deserving, or foreboding death by the halter.
      ``What a hanging face!'' --Dryden.

   2. Suspended from above; pendent; as, hanging shelves.

   3. Adapted for sustaining a hanging object; as, the hanging
      post of a gate, the post which holds the hinges.

   {Hanging compass}, a compass suspended so that the card may
      be read from beneath.

   {Hanging garden}, a garden sustained at an artificial
      elevation by any means, as by the terraces at Babylon.

   {Hanging indentation}. See under {Indentation}.

   {Hanging rail} (Arch.), that rail of a door or casement to
      which hinges are attached.

   {Hanging side} (Mining), the overhanging side of an inclined
      or hading vein.

   {Hanging sleeves}.
      (a) Strips of the same stuff as the gown, hanging down the
          back from the shoulders.
      (b) Loose, flowing sleeves.

   {Hanging stile}. (Arch.)
      (a) That stile of a door to which hinges are secured.
      (b) That upright of a window frame to which casements are
          hinged, or in which the pulleys for sash windows are
          fastened.

   {Hanging wall} (Mining), the upper wall of inclined vein, or
      that which hangs over the miner's head when working in the
      vein.

Source : WordNet®

hanging wall
     n : the upper wall of an inclined fault