gather

If people or things gather, they come together.

Example: A crowd of several hundred gathered outside the police station.

If you gather something, you've heard or read it, or you have reason to believe it, but you don't know.

Example: This trip was a kept secret, I gather, until yesterday.

If something gathers speed, it continues to get faster.

Example: The train pulled ahead, gathering speed as it moved away.

If something is gathering dust, it is not being used.

Example: Remember that wheelchair? It was gathering dust in the garage.