Filings are the tiny pieces of metal or other material that come off when you rub something against a file (a rough metal tool) or scrape it. If you file down a metal edge, the fine dust and small bits that fall off are called filings - 'iron filings' are a classic example from science class, often used to show how a magnet's invisible force field looks, because they line up along the magnetic field lines. This is a completely different thing from 'filing' a document, even though it looks like the same word.

（金屬等）銼屑、碎屑（如「鐵屑」iron filings）