armour plate vs plate armor

armour plate and plate armor both are nouns.

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

As nouns, armour plate and plate armor are synonyms defined as:

armour plate and plate armor: specially hardened steel plate used to protect fortifications or vehicles from enemy fire

Other synonyms of armour plate include armor plate, armor plating, plate armour.

armour plate (noun)	plate armor (noun)
specially hardened steel plate used to protect fortifications or vehicles from enemy fire	specially hardened steel plate used to protect fortifications or vehicles from enemy fire
	a historical type of personal armor made from iron or steel plates, which superseded mail during the 14th century.