chain armor vs ring mail

chain armor and ring mail both are nouns.

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

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

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

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

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