Mirror

Mirror
A place you can download a linux distribution iso or software from.

The term came from the real world object that is often found in bathrooms, a piece of shiny metal/glass that is used to reflect light and thus images.

In the virtual world, when a distro or piece of software is released, it is hosted on a server- the one that the project maintains. However, especially if the project is popular, the requests to download can be very taxing on the server's resources. So, other people with servers mirror (host a copy of) the downloadable file.

It is recommended that you pick a mirror that is close to you geographically- theoretically this increases speed because there is less cable to travel through.