ad vs commercial

ad and commercial both are nouns.

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

As nouns, commercial is a hyponym of ad; that is, commercial is a word with a more specific, narrower meaning than ad:

ad (noun)	commercial (noun)
a public promotion of some product or service	a commercially sponsored ad on radio or television

ad (adjective)	commercial (adjective)
	connected with or engaged in or sponsored by or used in commerce or commercial enterprises
	of or relating to commercialism
	of the kind or quality used in commerce; average or inferior
	profit oriented