GRIND v. 3 definitions
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.
GRINDSTONE n.
A flat, circular stone, revolving on an axle, for grinding or sharpening tools, or shaping or smoothing objects. To hold, pat, or bring one's nose to the grindstone, to oppress one; to keep one in a condition of servitude. They might be ashamed, for lack of courage, to suffer the Lacedæmonians to hold their noses to th…