The right is a subdirectory that corresponds to the category you highlighted.
From the usatoday.com
In a subdirectory they can include any copyright free or CC-BY-SA photographs or text.
From the en.wikipedia.org
These are often rewritten to resemble URLs for static pages on a site with a subdirectory hierarchy.
From the en.wikipedia.org
A folder contained inside another folder is called a subfolder, subdirectory, or child of that folder.
From the en.wikipedia.org
If you throw your content into a subdirectory, usually the code is all in the same file storage space.
From the mattcutts.com
On that machine, the government charged, Lee downloaded the data from the subdirectory onto 10 tapes.
From the time.com
Under GoboLinux, each program has its own subdirectory tree.
From the en.wikipedia.org
For example, a subdirectory of the source tree plus an associated global header file is a very common case.
From the en.wikipedia.org
For example, within a music library, all music files may be located within an artist folder, with an album subdirectory.
From the en.wikipedia.org
More examples
(computer science) a directory that is listed in another directory
Folder, directory, catalog, or drawer, in computing, is a virtual container within a digital file system, in which groups of computer files and other folders can be kept and organized.
An area on a hard disk that contains a related set of files; on IBM PC or compatibles, a level below another directory. On Macintoshes, subdirectories are referred to as folders.
In computer programming, directories located within directories as convenient structure for organizing files into easily found groups; like having address showing where files are located.