The naming convention in Cascade
There are different names inside of Cascade, each serving their own purpose.
Every page and folder needs a Display Name in order for it to show up in the navigation. Display Names are what show up in any automatically generated area on your website, such as the navigation, breadcrumbs and optional A to Z index of your site.
Both web browsers and search engines use Titles to identify which page is being displayed.
Every asset needs a system name to identify itself inside of Cascade as well as when it is published to a web server. Because this name will become part of the URL, avoid using spaces or special characters in the system name so users will be easily able to access each asset. Note that every folder needs a page with the system name of "default" inside so the navigation can work.