chain mail vs body armor

chain mail and body armor both are nouns.

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

As nouns, body armor is a hypernym of chain mail; that is, body armor is a word with a broader meaning than chain mail:

Other hypernyms of chain mail include body armour, cataphract, coat of mail, suit of armor, suit of armour.

chain mail (noun)	body armor (noun)
(Middle Ages) flexible armor made of interlinked metal rings	armor that protects the wearer's whole body