The Collaborative International Dictionary of English v.0.48:

Bucking \Buck"ing\, n.
   1. The act or process of soaking or boiling cloth in an
      alkaline liquid in the operation of bleaching; also, the
      liquid used. --Tomlinson.
      [1913 Webster]

   2. A washing.
      [1913 Webster]

   3. The process of breaking up or pulverizing ores.
      [1913 Webster]

   Bucking iron (Mining), a broad-faced hammer, used in
      bucking or breaking up ores.

   Bucking kier (Manuf.), a large circular boiler, or kier,
      used in bleaching.

   Bucking stool, a washing block.
      [1913 Webster]