noun plas·tron \ˈpla-strən\

Definition of plastron

  1. 1a :  a metal breastplate formerly worn under the hauberkb :  a quilted pad worn in fencing to protect the chest, waist, and the side on which the weapon is held

  2. 2 :  the ventral part of the shell of a tortoise or turtle consisting typically of nine symmetrically placed bones overlaid by horny plates

  3. 3a :  a trimming like a bib for a woman's dressb :  dickey 1a

  4. 4 :  a thin film of air held by water-repellent hairs of some aquatic insects

plastron was our Word of the Day on 01/09/2014. Hear the podcast!

Did You Know?

English speakers first borrowed French's word for a breastplate, plastron, as the name for the protective plate worn under a tunic of [chain mail](/dictionary/chain mail) by knights. In the 17th century, plastron was extended to the pad used to protect the torso of a fencer. Two centuries later, herpetologists appropriated the word for a slightly different type of protection: the underside of a turtle's shell, which consists typically of nine bones overlaid by horny plates. That was followed by the word's application in the world of fashion to coverings that adorn the front of a woman's bodice, such as a lacy bib, as well as to a man's separate or detachable starched shirtfront (which is typically worn under a jacket).

Origin and Etymology of plastron

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

First Known Use: circa 1507

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a trip made at another's expense

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