(Or "path") The specification of a node (file or directory) in a hierarchical file system. The path is usually specified by listing the nodes top-down, separating the directories by the pathname separator ("/" in Unix, "\" in MS-DOS).

A pathname may be an absolute pathname (starting from the root directory, "/") or a relative pathname (starting from the current working directory).

The part of the pathname of a file after the last separator is called the basename.