Whetstone \Whet"stone`\, n. [AS. hwetst[=a]n.]

A piece of stone, natural or artificial, used for whetting, or sharpening, edge tools.

The dullness of the fools is the whetstone of the wits. --Shak.

Diligence is to the understanding as the whetstone to the razor. --South.

Note: Some whetstones are used dry, others are moistened with water, or lubricated with oil.

To give the whetstone, to give a premium for extravagance in falsehood. [Obs.]

Source: Webster's Revised Unabridged Dictionary (1913)