The address that appears in the browser bar when you visit a webpage is also called an URL or “uniform resource locator”, an addressing protocol used for locating many internet resources, not just webpages. URLs have much in common with the directory structures used on hard discs. Both use a slash “/” (sometimes “\”) to indicate a subfolder.
In practice, modern websites often pull content from databases to create pages on the fly. Therefore, the browser address doesn’t necessarily tell you where everything is physically, and all that matters is that you have a structured way to retrieve it. (In fact, hard disks don’t store content in physically different folders either, they use a “file allocation table” to find them).
As an example, if the URL is
Jacksfiles.Smithfamily.com/photos/private/dodgyphoto.jpg, dodgyphoto.jpg is a file and “private” is a subfolder of the “photos” folder. Note that the hierarchy works …