greave vs armor plate

greave and armor plate both are nouns.

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

As nouns, armor plate is a hypernym of greave; that is, armor plate is a word with a broader meaning than greave:

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

Other hypernyms of greave include armor plating, armour plate, plate armor, plate armour.

greave (noun)	armor plate (noun)
armor plate that protects legs below the knee	specially hardened steel plate used to protect fortifications or vehicles from enemy fire