Main Entry: plas·tron

Pronunciation: \ˈplas-trən\

Function: noun

Etymology: Middle French, from Old Italian piastrone, augmentative of piastra thin metal plate — more at piastre

Date: circa 1507

1 a : a metal breastplate formerly worn under the hauberk b : a quilted pad worn in fencing practice to protect the chest, waist, and the side on which the weapon is held
2 : the ventral part of the shell of a tortoise or turtle consisting typically of nine symmetrically placed bones overlaid by horny plates
3 a : a trimming like a bib for a woman's dress b : dickey 1a
4 : a thin film of air held by water-repellent hairs of some aquatic insects