Directory

In computing, a directory is a node in a hierarchical file system which can contain other nodes, such as files or other directories (also known as subdirectories).

Description
The term "folder" is often used in systems such as the Macintosh or Microsoft Windows in which directories can be depicted as folders containing files and even more folders. The top level of the directory hierarchy is refered to as the root directory.

History
In the first Macintosh File System introduced by Apple Computer in January 1984, directories were actually cosmetic within a flat file system where all files were stored in the root directory, and folders could not contain folders. This was superseded by a true Hierarchical File System in September 1985.