ordnance vs artillery

ordnance and artillery both are nouns.

Word	Noun	Adjective	Verb	Adverb
ordnance	Yes	No	No	No
artillery	Yes	No	No	No

As nouns, ordnance and artillery are synonyms defined as:

Other synonyms of ordnance include gun, heavy weapon.

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