chain armour vs ring armor

chain armour and ring armor both are nouns.

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

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

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

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

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