Source : Webster's Revised Unabridged Dictionary (1913)

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.

            Take the millstones, and grind meal.  --Is. xivii.
                                                  2.

   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.

   3. To oppress by severe exactions; to harass.

            To grind the subject or defraud the prince.
                                                  --Dryden.

   4. To study hard for examination. [College Slang]

Grinding \Grind"ing\, a. & n.
   from Grind.

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

   {Grinding mill}.
   (a) A mill for grinding grain.
   (b) A lapidary's lathe.

Source : WordNet®

grinding
     n 1: matter 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: {abrasion}, {attrition}, {detrition}]