chain mail vs ring mail

chain mail and ring mail both are nouns.

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

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

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

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

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