ad vs advertizement

ad and advertizement both are nouns.

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

As nouns, ad and advertizement are synonyms defined as:

Other synonyms of ad include advert, advertisement, advertising, advertizing.

ad (noun)	advertizement (noun)
a public promotion of some product or service	a public promotion of some product or service