A common application found in projects. Simple projects may only have two applications, often called [wikie:ref/DirFrontend frontend] and backend. This is only a convention; applications within a project can have any name the developer wishes. The backend application is generally intended for administrative access to the project.
There is no implication that the backend occurs on the server and the frontend on the client. They are both just application names. The backend is usually for tasks that the general user of the frontend shouldn't be able to perform. It provides a convenient division for security and authentication. Administrative access could be provided via different modules? within an application, but it is not normally done that way.
listing from Jobeet:
> ls -l apps/backend drwxr-xr-x 12 user staff 408 Jan 15 11:18 config drwxr-xr-x 3 user staff 102 Jan 5 15:24 i18n drwxr-xr-x 4 user staff 136 Jan 7 15:04 lib drwxr-xr-x 6 user staff 204 Jan 15 10:21 modules drwxr-xr-x 4 user staff 136 Jan 15 10:30 templates