The Collaborative International Dictionary of English v.0.48:

Whetstone \Whet"stone`\, n. [AS. hwetst[=a]n.]
   A piece of stone, natural or artificial, used for whetting,
   or sharpening, edge tools.
   [1913 Webster]

         The dullness of the fools is the whetstone of the wits.
                                                  --Shak.
   [1913 Webster]

         Diligence is to the understanding as the whetstone to
         the razor.                               --South.
   [1913 Webster]

   Note: Some whetstones are used dry, others are moistened with
         water, or lubricated with oil.
         [1913 Webster]

   To give the whetstone, to give a premium for extravagance
      in falsehood. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

whetstone
    n 1: a flat stone for sharpening edged tools or knives

The Free On-line Dictionary of Computing (19 January 2023):

Whetstone

    The first major synthetic benchmark program,
   intended to be representative for numerical (floating-point
   intensive) programming.  It is based on statistics gathered by
   Brian Wichmann at the National Physical Laboratory in
   England, using an Algol 60 compiler which translated Algol
   into instructions for the imaginary Whetstone machine.  The
   compilation system was named after the small town of Whetstone
   outside the City of Leicester, England, where it was designed.

   The later dhrystone benchmark was a pun on Whetstone.

   Source code: C
   (ftp://netlib.att.com/netlib/benchmark/whetstonec.Z), single
   precision Fortran
   (ftp://netlib.att.com:/netlib/benchmark/whetstones.Z),
   double precision Fortran
   (ftp://netlib.att.com:/netlib/benchmark/whetstoned.Z).

   ["A Synthetic Benchmark", H.J. Curnow and B.A. Wichmann, The
   Computer Journal, 19,1 (1976), pp. 43-49].

   (1994-11-14)