plate armour vs cuisse

plate armour and cuisse both are nouns.

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

As nouns, cuisse is a hyponym of plate armour; that is, cuisse 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
cuisse: armor plate that protects the thigh

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a historical type of personal armor made from iron or steel plates, which superseded mail during the 14th century.