armour plate vs armor plate

armour plate and armor plate both are nouns.

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

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

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

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

armour plate (noun)	armor plate (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