coat of mail vs armor

coat of mail and armor both are nouns.

Word	Noun	Adjective	Verb	Adverb
coat of mail	Yes	No	No	No
armor	Yes	No	Yes	No

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

Other hypernyms of coat of mail include armour.

coat of mail (noun)	armor (noun)
armor that protects the wearer's whole body	tough more-or-less rigid protective covering of an animal or plant
	protective covering made of metal and used in combat
	a military unit consisting of armored fighting vehicles

coat of mail (verb)	armor (verb)
	equip with armor