whetstone

Etymology

From Middle English whestone, whetston, whetesston, from Old English hwetstān, hwettstān, hwetestān, equivalent to whet (“to sharpen”) +‎ stone.

Noun

whetstone (plural whetstones)

1. A sharpening stone; a hard stone or piece of synthetically bonded hard minerals that has been formed with at least one flat surface, used to sharpen or hone an edged tool.
   • 1922, Virginia Woolf, Jacob's Room, Vintage Classics, paperback edition, page 88-89

     It was as if a stone were ground to dust; as if white sparks flew from a livid whetstone, which was his spine; as if the switchback railway, having swooped to the depths, fell, fell, fell.

2. (computing) A benchmark for evaluating the power and performance of a computer.
3. (figuratively) A stimulant.