ring armour vs ring armor

ring armour and ring armor both are nouns.

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

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

ring armour and ring armor: (Middle Ages) flexible armor made of interlinked metal rings

Other synonyms of ring armour include chain armor, chain armour, chain mail, mail, ring mail.

ring armour (noun)	ring armor (noun)
(Middle Ages) flexible armor made of interlinked metal rings	(Middle Ages) flexible armor made of interlinked metal rings