phonebook vs directory

phonebook and directory both are nouns.

Word	Noun	Adjective	Verb	Adverb
phonebook	Yes	No	No	No
directory	Yes	No	No	No

As nouns, directory is a hypernym of phonebook; that is, directory is a word with a broader meaning than phonebook:

phonebook: a directory containing an alphabetical list of telephone subscribers and their telephone numbers
directory: an alphabetical list of names and addresses

phonebook (noun)	directory (noun)
a directory containing an alphabetical list of telephone subscribers and their telephone numbers	an alphabetical list of names and addresses
	(computer science) a listing of the files stored in memory (usually on a hard disk)