The Collaborative International Dictionary of English v.0.48:

Buck \Buck\, v. t. [imp. & p. p. Bucked (b[u^]kt); p. pr. &
   vb. n. Bucking.] [OE. bouken; akin to LG. b["u]ken, Dan.
   byge, Sw. byka, G. bauchen, beuchen; cf. OF. buer. Cf. the
   preceding noun.]
   1. To soak, steep, or boil, in lye or suds; -- a process in
      bleaching.
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   2. To wash (clothes) in lye or suds, or, in later usage, by
      beating them on stones in running water.
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   3. (Mining) To break up or pulverize, as ores.
      [1913 Webster]