Breastplate

n.	1.	A plate of metal covering the breast as defensive armor. Before his old rusty breastplate could be scoured, and his cracked headpiece mended. - Swift.
	2.	A piece against which the workman presses his breast in operating a breast drill, or other similar tool.
	3.	A strap that runs across a horse's breast.
	4.	(Jewish Antiq.) A part of the vestment of the high priest, worn upon the front of the ephod. It was a double piece of richly embroidered stuff, a span square, set with twelve precious stones, on which were engraved the names of the twelve tribes of Israel. See Ephod.

Noun

1.

breastplate - armor plate that protects the chest; the front part of a cuirass Synonyms: egis, aegis

aegis, armor plate, armor plating, armour plate, body armor, body armour, cataphract, coat of mail, egis, plastron, plate armor, plate armour, suit of armor, suit of armour