ring mail vs ring armour

ring mail and ring armour both are nouns.

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

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

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

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

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