armour vs body armor

armour and body armor both are nouns.

Word	Noun	Adjective	Verb	Adverb
armour	Yes	No	Yes	No
body armor	Yes	No	No	No

As nouns, body armor is a hyponym of armour; that is, body armor is a word with a more specific, narrower meaning than armour:

Other hyponyms of armour include body armour, cataphract, coat of mail, suit of armor, suit of armour, buckler, shield.

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

armour (verb)	body armor (verb)
equip with armor