to sharpen a knife with a whishing or whistling sound [[霍霍|霍霍|huo4 huo4]]; originally describing Mulan's brother preparing to slaughter livestock

grindstone or stone block used for sharpening knives and blades

literally meaning that sharpening the knife will not delay the woodcutting; time spent on preparation is not wasted and will improve efficiency later

a fine-grained whetstone used specifically for honing knives