·noun An iron breastplate, worn under the hauberk.
II. Plastron ·noun A piece of leather stuffed or padded, worn by fencers to protect the breast.
III. Plastron ·noun The ventral shield or shell of tortoises and turtles. ·see Testudinata.
IV. Plastron ·noun A trimming for the front of a woman's dress, made of a different material, and narrowing from the shoulders to the waist.