Plastron

Definition:

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

Compare plastron with other words:

hypoplastron vs. plastron