byrnie vs ring mail

byrnie and ring mail both are nouns.

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

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

byrnie: 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 byrnie include chain armor, chain armour, chain mail, mail, ring armor, ring armour.

byrnie (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