갈다

1. sharpen; hone
To rub one thing against another to make the edge shaper.

2. sharpen; hone
To rub one thing against another to make its surface smooth or polished.

3. grind; mince
To rub or crush one thing against another to break it up into small particles or reduce it to powder.

4. rub an ink stick
To rub an ink stick against an ink stone to generate India ink.

5. grind one's teeth
To make a sound by rubbing one's lower teeth against upper teeth.