Quiz: Remember the definition of mal de mer?
1540s, "guide, book of rules," from Medieval Latin directorium, noun use of neuter of Latin directorius, from directus (see direct (v.)). Meaning "alphabetical listing of inhabitants of a region" is from 1732; listing of telephone numbers is from 1908. As an adjective, from mid-15c.
A node in a hierarchical file system which contains zero or more other nodes - generally, files or other directories.
The term "folder" is sometimes used in systems such as the Macintosh or Microsoft Windows in which directories are traditionally depicted as folders (like small briefcases).