chain armor vs ring armour

chain armor and ring armour both are nouns.

Word	Noun	Adjective	Verb	Adverb
chain armor	Yes	No	No	No
ring armour	Yes	No	No	No

As nouns, chain armor and ring armour are synonyms defined as:

chain armor and ring armour: (Middle Ages) flexible armor made of interlinked metal rings

Other synonyms of chain armor include chain armour, chain mail, mail, ring armor, ring mail.

chain armor (noun)	ring armour (noun)
(Middle Ages) flexible armor made of interlinked metal rings	(Middle Ages) flexible armor made of interlinked metal rings