Dust is very small dry particles of earth or sand.

Dust is the very small pieces of dirt which you find inside buildings, for example on furniture, floors, or lights.

Dust is a fine powder which consists of very small particles of a substance such as gold, wood, or coal.

When you dust something such as furniture, you remove dust from it, usually using a cloth.

If you dust something with a fine substance such as powder or if you dust a fine substance onto something, you cover it lightly with that substance.

If you say that something has bitten the dust, you are emphasizing that it no longer exists or that it has failed.

If you say that something will happen when the dust settles, you mean that a situation will be clearer after it has calmed down. If you let the dust settle before doing something, you let a situation calm down before you try to do anything else.

If you say that something is gathering dust, you mean that it has been left somewhere and nobody is using it or doing anything with it.