cookbook vs reference book

cookbook and reference book both are nouns.

Word	Noun	Adjective	Verb	Adverb
cookbook	Yes	No	No	No
reference book	Yes	No	No	No

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

Other hypernyms of cookbook include book of facts, reference, reference work.

cookbook (noun)	reference book (noun)
a book of recipes and cooking directions	a book to which you can refer for authoritative facts