A web page URL is a file name, just like filename.jpg, filename.doc, or, as in the case of a web page, filename.html.  The page URL is the part that comes after the domain, such as 'domain.com/page-url.' In some cases, there might be a subfolder preceding the Page URL, like 'domain.com/sub-folder/page-url.' The combination of the subfolder and Page URL forms the complete page name. 

Search engines and people read the page name for clues about what the page is about. The more clear and understandable the page name is, the easier it is for search engines to find the page and, at the same time, give users confidence in visiting the page.

Note:  In HWP, the Page URL is the page name.