ring armor vs cataphract

ring armor and cataphract both are nouns.

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

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

Other hypernyms of ring armor include body armor, body armour, coat of mail, suit of armor, suit of armour.

ring armor (noun)	cataphract (noun)
(Middle Ages) flexible armor made of interlinked metal rings	armor that protects the wearer's whole body