chain mail vs ring armour

chain mail and ring armour both are nouns.

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

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

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

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

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