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.
      [1913 Webster]

   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.
      [1913 Webster]

   3. To oppress by severe exactions; to harass.
      [1913 Webster]

            To grind the subject or defraud the prince.
                                                  --Dryden.
      [1913 Webster]

   4. To study hard for examination; -- commonly used with away;
      as, to grind away at one's studies. [College Slang]
      [1913 Webster]

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]

Moby Thesaurus II by Grady Ward, 1.0:

151 Moby Thesaurus words for "grinding":
   ablation, ablative, abradant, abrasion, abrasive, absolute,
   absolutist, absolutistic, application, arbitrary, aristocratic,
   arrogant, atomization, attrition, attritive, authoritarian,
   authoritative, autocratic, beating, boning, bossy, brainwork,
   brecciation, buffing, burdensome, burnishing, chafe, chafing,
   comminution, conning, contemplation, cram, cramming, crumbling,
   crushing, despotic, detrition, dictatorial, disintegration,
   domineering, dressing, drill, drudging, engrossment, erasure,
   erosion, erosive, exercise, exhausting, extensive study, feudal,
   filing, fragmentation, fretting, galling, gnawing, granulation,
   granulization, grating, grazing, grind, grubbing, hardworking,
   harsh, headwork, heavy, high-handed, imperative, imperial,
   imperious, inspection, irritant, irritating, irritative, jangling,
   jangly, jarring, laboring, levigation, limation, lordly,
   lucubration, magisterial, magistral, mashing, masterful,
   mental labor, monocratic, onerous, oppressive, overbearing,
   overburdensome, overruling, pegging, peremptory, perusal, plodding,
   plugging, polishing, pounding, powdering, practice, rasping, raspy,
   reading, repressive, restudy, restudying, review, rubbing away,
   sandblasting, sanding, scouring, scrape, scraping, scrapy, scratch,
   scratching, scratchy, scrub, scrubbing, scuff, severe, shining,
   shredding, slaving, slogging, smashing, smoothing, stinging,
   straining, strict, striving, struggling, study, studying, subject,
   suppressive, sweating, swotting, toiling, trituration, tyrannical,
   tyrannous, wear, wearing, wearing away, wearying, weighty,
   wide reading, working