plastron

noun

plas·​tron ˈpla-strən 

1

a

: a metal breastplate formerly worn under the hauberk

b

: a quilted pad worn in fencing 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 sense 1a

4

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

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).

Examples of plastron in a Sentence

Recent Examples on the Web

The second had string binding all four flippers along with its neck and plastron (underside). —Danielle Beurteaux, Smithsonian Magazine, 18 Oct. 2024

Software simulations helped the atelier carve rock crystal into a precious interpretation of the ripples caused by a falling drop for a plastron necklace that conformed to the body. —Lily Templeton, WWD, 12 July 2024

Her report noted the juvenile turtle had a few abrasions on its plastron, or shell, with an open hole or sore near a long crack near its back left flipper. —Kori Rumore, Chicago Tribune, 20 July 2023

Box turtles get their name from the hinged plastron (lower shell). —Arkansas Online, 20 June 2022

To fix the plastron, the center's veterinarian worked with her father, a professor at Marquette University School of Dentistry. —Evan Frank, Milwaukee Journal Sentinel, 1 Nov. 2019

Feavel said the turtle was likely hit by a vehicle, which fractured the skull, carapace (top shell) and plastron (bottom shell). —Evan Frank, Milwaukee Journal Sentinel, 1 Nov. 2019

The domed carapace covering the back of the animal is connected to the flat plastron on the underside of the animal by a bridge of bone. —Hans-Dieter Sues, Smithsonian, 20 Aug. 2019

The origin of the plastron covering the underside of the turtle is less obvious. —Hans-Dieter Sues, Smithsonian, 20 Aug. 2019

Word History

Etymology

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

First Known Use

circa 1507, in the meaning defined at sense 1a

Rhymes for plastron

• gastrin

Podcast

Get Word of the Day delivered to your inbox!