meaning of breastplate
1.  A plate of metal covering the breast as defensive armor. 
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 horses breast. 
4.  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. 
						 
