testiere vs plate armour

testiere and plate armour both are nouns.

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

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

testiere: medieval plate armor to protect a horse's head
plate armour: specially hardened steel plate used to protect fortifications or vehicles from enemy fire

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

testiere (noun)	plate armour (noun)
medieval plate armor to protect a horse's head	specially hardened steel plate used to protect fortifications or vehicles from enemy fire
	a historical type of personal armor made from iron or steel plates, which superseded mail during the 14th century.