advertizement vs promo

advertizement and promo both are nouns.

Word	Noun	Adjective	Verb	Adverb
advertizement	Yes	No	No	No
promo	Yes	No	No	No

As nouns, promo is a hypernym of advertizement; that is, promo is a word with a broader meaning than advertizement:

advertizement: a public promotion of some product or service
promo: a message issued in behalf of some product or cause or idea or person or institution

Other hypernyms of advertizement include packaging, promotion, promotional material, publicity.

advertizement (noun)	promo (noun)
a public promotion of some product or service	a message issued in behalf of some product or cause or idea or person or institution