plate armor vs jambeau

plate armor and jambeau both are nouns.

Word	Noun	Adjective	Verb	Adverb
plate armor	Yes	No	No	No
jambeau	Yes	No	No	No

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

plate armor: specially hardened steel plate used to protect fortifications or vehicles from enemy fire
jambeau: armor plate that protects legs below the knee

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a historical type of personal armor made from iron or steel plates, which superseded mail during the 14th century.