Cách sử dụng
A grindstone is a flat, circular tool made of stone or metal that is used for sharpening or smoothing edges of tools, blades, or other objects. It is often used in woodworking, metalworking or outdoor activities such as hiking or camping, where sharp tools are necessary. The phrase "putting one's nose to the grindstone" means working hard or diligently, with a focus to achieve a goal.