hauberk vs ring mail

hauberk and ring mail both are nouns.

Word	Noun	Adjective	Verb	Adverb
hauberk	Yes	No	No	No
ring mail	Yes	No	No	No

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

hauberk: a long (usually sleeveless) tunic of chain mail formerly worn as defensive armor
ring mail: (Middle Ages) flexible armor made of interlinked metal rings

Other hypernyms of hauberk include chain armor, chain armour, chain mail, mail, ring armor, ring armour.

hauberk (noun)	ring mail (noun)
a long (usually sleeveless) tunic of chain mail formerly worn as defensive armor	(Middle Ages) flexible armor made of interlinked metal rings