Brĕast'plāte, n.

n. 1. A plate worn upon the breast as a part of defensive armor. “Before his old rusty breastplate could be scoured, and his cracked head-piece mended.” Swift.

2. A plate or piece which receives the end of a drill, and gives pressure to it by being held against the breast when the tool is in use. Francis.
3. A strap that runs across a horse’s breast.
4. (Jewish Antiq.) A part of the vestment of the high priest, consisting of a folded piece of the rich, embroidered stuff of which the ephod was made. It was set with twelve precious stones, on which were engraved the names of the twelve tribes. [See Illust. of Ephod.]