four-pounder vs artillery

four-pounder and artillery both are nouns.

Word	Noun	Adjective	Verb	Adverb
four-pounder	Yes	No	No	No
artillery	Yes	No	No	No

As nouns, artillery is a hypernym of four-pounder; that is, artillery is a word with a broader meaning than four-pounder:

Other hypernyms of four-pounder include gun, heavy weapon, ordnance.

four-pounder (noun)	artillery (noun)
an artillery gun that throws a shot weighing four pounds	large but transportable armament
	a means of persuading or arguing
	an army unit that uses big guns