...that installing to a separate partition could be considered a "Clean Install" in that you are not upgrading over top of an existing version of Windows, but then you are actually setting up a dual-boot configuration. Dual-booting is a perfectly fine solution and you can choose to go that route instead, but it is not what this article is about.

In the case of this article, a "Clean Install" refers to wiping your hard disk "clean" and then installing a new operating system.