chain mail vs chain armor

chain mail and chain armor both are nouns.

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

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

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

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

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