The Collaborative International Dictionary of English v.0.48:

Grind \Grind\, v. t. [imp. & p. p. Ground; p. pr. & vb. n.
   Grinding.] [AS. grindan; perh. akin to L. frendere to
   gnash, grind. Cf. Grist.]
   1. To reduce to powder by friction, as in a mill, or with the
      teeth; to crush into small fragments; to produce as by the
      action of millstones.
      [1913 Webster]

            Take the millstones, and grind meal.  --Is. xivii.
                                                  2.
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   2. To wear down, polish, or sharpen, by friction; to make
      smooth, sharp, or pointed; to whet, as a knife or drill;
      to rub against one another, as teeth, etc.
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   3. To oppress by severe exactions; to harass.
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            To grind the subject or defraud the prince.
                                                  --Dryden.
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   4. To study hard for examination; -- commonly used with away;
      as, to grind away at one's studies. [College Slang]
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The Collaborative International Dictionary of English v.0.48:

Grinding \Grind"ing\, a. & n.
   from Grind.
   [1913 Webster]

   Grinding frame, an English name for a cotton spinning
      machine.

   Grinding mill.
   (a) A mill for grinding grain.
   (b) A lapidary's lathe.
       [1913 Webster]

WordNet (r) 3.0 (2006):

grinding
    n 1: material resulting from the process of grinding; "vegetable
         grindings clogged the drain"
    2: a harsh and strident sound (as of the grinding of gears)
    3: the wearing down of rock particles by friction due to water
       or wind or ice [syn: grinding, abrasion, attrition,
       detrition]