plate armour vs fauld

plate armour and fauld both are nouns.

Word	Noun	Adjective	Verb	Adverb
plate armour	Yes	No	No	No
fauld	Yes	No	No	No

As nouns, fauld is a hyponym of plate armour; that is, fauld is a word with a more specific, narrower meaning than plate armour:

plate armour: specially hardened steel plate used to protect fortifications or vehicles from enemy fire
fauld: a piece of armor plate below the breastplate

plate armour (noun)	fauld (noun)
specially hardened steel plate used to protect fortifications or vehicles from enemy fire	a piece of armor plate below the breastplate
a historical type of personal armor made from iron or steel plates, which superseded mail during the 14th century.