breastplate vs armor plating

breastplate and armor plating both are nouns.

Word	Noun	Adjective	Verb	Adverb
breastplate	Yes	No	No	No
armor plating	Yes	No	No	No

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

breastplate: armor plate that protects the chest; the front part of a cuirass
armor plating: specially hardened steel plate used to protect fortifications or vehicles from enemy fire

Other hypernyms of breastplate include armor plate, armour plate, plate armor, plate armour.

breastplate (noun)	armor plating (noun)
armor plate that protects the chest; the front part of a cuirass	specially hardened steel plate used to protect fortifications or vehicles from enemy fire