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