ring armor vs ring mail

ring armor and ring mail both are nouns.

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

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

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

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

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