From 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]
From The Collaborative International Dictionary of English v.0.48:
Grind \Grind\, v. i. 1. To perform the operation of grinding something; to turn the millstones. [1913 Webster]
Send thee Into the common prison, there to grind. --Milton. [1913 Webster]
2. To become ground or pulverized by friction; as, this corn grinds well. [1913 Webster]
3. To become polished or sharpened by friction; as, glass grinds smooth; steel grinds to a sharp edge. [1913 Webster]
4. To move with much difficulty or friction; to grate. [1913 Webster]
5. To perform hard and distasteful service; to drudge; to study hard, as for an examination. --Farrar. [1913 Webster]
From The Collaborative International Dictionary of English v.0.48:
Grind \Grind\, n. 1. The act of reducing to powder, or of sharpening, by friction. [1913 Webster]
2. Any severe continuous work or occupation; esp., hard and uninteresting study. [Colloq.] --T. Hughes. [1913 Webster]
3. A student that studies hard; a dig; a wonk. [College Slang] [1913 Webster +PJC]