ring mail vs chain armour

ring mail and chain armour both are nouns.

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

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

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

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

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