whetstone \ˈ ̷ ̷ˌ ̷ ̷\noun Etymology: Middle English whetston, from Old English hwetstān, from hwettan to whet + stān stone 1.: a natural or artificial stone for whetting edge tools < a blade sharpened on a well-oiled whetstone > 2.: something that sharpens, makes keen, or stimulates (as the wit or the appetite) < the dullness of the fool is the whetstone of the wits — Shakespeare >