arms vs naval weaponry

arms and naval weaponry both are nouns.

Word	Noun	Adjective	Verb	Adverb
arms	Yes	No	No	No
naval weaponry	Yes	No	No	No

As nouns, naval weaponry is a hyponym of arms; that is, naval weaponry is a word with a more specific, narrower meaning than arms:

Other hyponyms of arms include ammo, ammunition, armament, bomb, defence system, defense system, gunnery, hardware.

arms (noun)	naval weaponry (noun)
weapons considered collectively	weaponry for warships
the official symbols of a family, state, etc.