/brest"playt'/ , n.
1. a piece of plate armor partially or completely covering the front of the torso: used by itself or as part of a cuirass. See diag. under armor .
2. the part of the harness that runs across the chest of a saddle horse.
3. Judaism.
a. a square, richly embroidered vestment ornamented with 12 precious stones, each inscribed with the name of one of the 12 tribes of Israel, secured to the ephod of the high priest and worn on the chest. Ex. 28:15-28.
b. a rectangular ornament, typically of silver, suspended by a chain over the front of a scroll of the Torah.
4. a plate opposite the chuck end of a breast drill against which the operator's chest is placed.
[ 1350-1400; ME brestplate. See BREAST, PLATE 1 ]