[′shär·pə·niŋ ‚stōn] (engineering) A device such as a whetstone used for sharpening by hand.
whetstone
A piece of stone, natural or artificial, used to sharpen cutting tools.
sharpening stone
shar·pen·ing stone
(shahrpĕn-ing stōn) Natural or synthetic stone composed of abrasive particles used to restore a sharp cutting edge on a calculus removal instrument. FinancialSeeStone