A folder is a storage place for documents and files. Incomputers, folders are structured hierarchically in a directory tree. Such a directory tree consists of the main folder, to which any number of subfolders and files can be subordinated.
If the main folder is A, then the first hierarchy may consist of subfolders AA, AB, AC, and so on. If the subfolder AB is assigned further subfolder groups, then these are the subfolders ABA, ABB, ABC, etc. In the directory tree the folders are separated from each other by a backslash: A\AB\ABA.
A hierarchical folder system should consist of self-explanatory, higher- level terms, for example, employees, incoming orders, invoices, and so on. The subfolders for employees could then be departmentalized.