rubstone

[ ruhb-stohn ]
/ ˈrʌbˌstoʊn /

noun

a stone, especially a whetstone, used for polishing or sharpening.

Origin of rubstone

late Middle English word dating back to 1400–50; see origin at rub, stone

British Dictionary definitions for rubstone

rubstone
/ (ˈrʌbˌstəʊn) /

noun

a stone used for sharpening or smoothing, esp a whetstone