1 the ornamental front of a woman's bodice or shirt
2 the front of man's dress shirt
3 a metal breastplate that was worn under a coat of mail
4 a large pad worn by a fencer to protect the chest
5 (zoology) the part of a turtle's shell forming its underside
EtymologyFrom French plastron, from Italian piastrone, augmentive of piastra ‘breastplate’, from Latin emplastrum ‘plaster’, from Ancient Greek , from ‘daubed, plastered’, from ‘to mould, form’.
- The nearly flat part of the shell structure of a tortoise or other animal, similar in composition to the carapace
- A half-jacket worn under the jacket for padding or for safety.
- An ornamental front panel on a woman's bodice.
- 1942: I bought here a wedding dress perhaps twenty or thirty years old [...] a sequin plastron to be worn over the womb as a feminine equivalent to a cod-piece, and a gauze veil embroidered in purple and gold. — Rebecca West, Black Lamb and Grey Falcon (Canongate 2006, p. 784)
The plastron is the nearly flat part of the shell structure of a turtle or tortoise, what one would call the belly, similar in composition to the carapace; with an external layer of horny material divided into plates called scutes and an underlying layer of interlocking bones.
In certain families there is a hinge between the pectoral and abdominal scutes allowing the turtle to almost completely enclose itself. In certain species the sex of a testudine can be told by whether the plastron is concave, male or convex, female. This is because of the mating position.
The plastral scutes join along a central seam down the middle of the plastron. The relative lengths of the seam segments can be used to help identify a species of turtle or tortoise. There are six laterally symmetric pairs of scutes on the plastron: gular, humeral, pectoral, abdominal, femoral, and anal (going from the head to the tail down the seam).
Indicating that the abdominal and gular scute seams are approximately the same length and the the femoral and pectoral seams are approximately the same length. Comparison of the plastral formulas provides distinction between the two species.
Turtle plastrons were used by the ancient Chinese in a type of divination called plastromancy. See also oracle bones.
Plastron is also a name that's been given to various coverings or structures on the ventral (belly) side of some creatures, people or objects.
- "Plastron" is the name of a broad piece of material placed on the chest of certain military uniforms and held in place by two rows of buttons. The plastron was a popular feature of military dress during the period 1800-1914, when it was commonly worn by lancer and uhlan regiments in various European armies. It was also worn by light dragoon regiments in the British Army and by infantry and artillery units in the Imperial Russian Army. Plastrons were usually in contrasting colours to those of the tunics or coats that they were attached to.
- The name of the bulge on an aircraft, such as the Airbus A340, under the fuselage between the wings that is used to correct airflow around the engine pylons. On many aircraft, this bulge also helps house the main undercarriage when retracted.
- A "plastron" is also a thin permanent layer of air around the body of some aquatic insects, held in place by hydrophobic hairs, and acting as a physical gill.
- "Plastron" is also the name of a one-arm, half-jacket used in the sport of fencing.
- "Plastron" the name of a leading global manufacturer of precision coil bobbins for the electronics industry. Founded in 1970, it is now part of Cosmo Corporation.
plastron in Bulgarian: Пластрон
plastron in Catalan: Plastró
plastron in German: Plastron (Biologie)
plastron in French: Carapace de tortue
plastron in Dutch: Plastron
plastron in Polish: Plastron (zoologia)