丸まる砥と石いし

noun

grindstone; round whetstone

A round stone used for sharpening or grinding tools. The term is straightforward and refers to the physical object.

• 職しょく人にんは丸まる砥と石いしで包ほう丁ちょうを研といだ。

  The craftsman sharpened the knife with a round grindstone.