heavy weapon vs artillery

heavy weapon and artillery both are nouns.

Word	Noun	Adjective	Verb	Adverb
heavy weapon	Yes	No	No	No
artillery	Yes	No	No	No

As nouns, heavy weapon and artillery are synonyms defined as:

Other synonyms of heavy weapon include gun, ordnance.

heavy weapon (noun)	artillery (noun)
large but transportable armament	large but transportable armament
	a means of persuading or arguing
	an army unit that uses big guns