ring mail vs habergeon

ring mail and habergeon both are nouns.

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

As nouns, habergeon is a hyponym of ring mail; that is, habergeon is a word with a more specific, narrower meaning than ring mail:

ring mail: (Middle Ages) flexible armor made of interlinked metal rings
habergeon: (Middle Ages) a light sleeveless coat of chain mail worn under the hauberk

Other hyponyms of ring mail include brigandine, byrnie, hauberk, gusset, voider.

ring mail (noun)	habergeon (noun)
(Middle Ages) flexible armor made of interlinked metal rings	(Middle Ages) a light sleeveless coat of chain mail worn under the hauberk