coat of mail vs armour

coat of mail and armour both are nouns.

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

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

Other hypernyms of coat of mail include armor.

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