Noun

1. A piece of defensive armor, covering the body from the neck to the girdle.
   • 1786, Francis Grose, A Treatise on Ancient Armour and Weapons, page 19:

     The cuirass covered the body before and behind, it consisted of two parts, a breast and back piece of iron, fastened together by means of straps and buckles, or other contrivances. They were originally as the name imports, made of leather, but afterwards of metal, both brass and iron.

1. The breastplate taken by itself.