arms vs weaponry

arms and weaponry both are nouns.

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

As nouns, arms and weaponry are synonyms defined as:

Other synonyms of arms include implements of war, munition, weapons system.

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