button ad vs ad

button ad and ad both are nouns.

Word	Noun	Adjective	Verb	Adverb
button ad	Yes	No	No	No
ad	Yes	No	No	No

As nouns, ad is a hypernym of button ad; that is, ad is a word with a broader meaning than button ad:

button ad: small circular, rectangular, or square advertisement appearing usually at the bottom of a webpage.
ad: a public promotion of some product or service

Other hypernyms of button ad include advert, advertisement, advertising, advertizement, advertizing.

button ad (noun)	ad (noun)
small circular, rectangular, or square advertisement appearing usually at the bottom of a webpage.	a public promotion of some product or service