blurb vs promotional material

blurb and promotional material both are nouns.

Word	Noun	Adjective	Verb	Adverb
blurb	Yes	No	No	No
promotional material	Yes	No	No	No

As nouns, promotional material is a hypernym of blurb; that is, promotional material is a word with a broader meaning than blurb:

blurb: a promotional statement (as found on the dust jackets of books)
promotional material: a message issued in behalf of some product or cause or idea or person or institution

Other hypernyms of blurb include packaging, promo, promotion, publicity.

blurb (noun)	promotional material (noun)
a promotional statement (as found on the dust jackets of books)	a message issued in behalf of some product or cause or idea or person or institution