Grindstone
Pronunciation : Grind"stone`
Part of Speech : n.
Definition : Defn: 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 Laced?monians to hold their noses to the grindstone. Sir T. North.
Source : Webster's Unabridged Dictionary, 1913