white pages vs phone book

white pages and phone book both are nouns.

Word	Noun	Adjective	Verb	Adverb
white pages	Yes	No	No	No
phone book	Yes	No	No	No

As nouns, phone book is a hypernym of white pages; that is, phone book is a word with a broader meaning than white pages:

white pages: a telephone directory or section of a directory (usually printed on white paper) where the names of people are listed alphabetically along with their telephone numbers
phone book: a directory containing an alphabetical list of telephone subscribers and their telephone numbers

Other hypernyms of white pages include phonebook, telephone book, telephone directory.

white pages (noun)	phone book (noun)
a telephone directory or section of a directory (usually printed on white paper) where the names of people are listed alphabetically along with their telephone numbers	a directory containing an alphabetical list of telephone subscribers and their telephone numbers