wordbook vs book of facts

wordbook and book of facts both are nouns.

Word	Noun	Adjective	Verb	Adverb
wordbook	Yes	No	No	No
book of facts	Yes	No	No	No

As nouns, book of facts is a hypernym of wordbook; that is, book of facts is a word with a broader meaning than wordbook:

Other hypernyms of wordbook include reference, reference book, reference work.

wordbook (noun)	book of facts (noun)
a reference book containing words (usually with their meanings)	a book to which you can refer for authoritative facts