plastron
(ˈplæstrən)
Also 6 plasteroun.
[a. F. plastron breast-plate, also in other senses as in Eng., ad. It. piastrone, augment. of piastra breast-plate, prop. plate of metal; see piastre, plaster.]
1. a. A steel breast-plate formerly worn beneath the hauberk. Obs. exc. Hist.
| 1506–7 Acc. Ld. High Treas. Scot. III. 367 Item, for ane hebreschoun.., and ane plasteroun to the samyn. 1834 J. R. Planché Brit. Costume 87 In later times we shall find the plastron called the gorget. 1837 H. Ainsworth Crichton II. 392 The point of his lance glanced off the sharp gorget of the plastron. 1853 James Agnes Sorel (1860) I. 45, I should be thrown on one side like a rusty plastron. |
b. A leather-covered wadded shield or pad, worn by professional fencers over the breast.
| 1693 Dryden Juvenal vi. (1697) 134 Against the Post their wicker Shields they crush, Flourish the Sword, and at the Plastron push. 1706 Phillips, Plastron, a Fencing-Master's quilted Breast-Leather, which serves for his Scholars to push at. 1893 McCarthy Red Diamonds I. 261 Endeavouring to plant her foil on the leather plastron of the fencing-master's chest. |
| transf. a 1648 Digby Closet Open. (1677) 162 Laying under it a thick Plastron of Beef-Suet. |
| fig. 1755 Chesterfield Let. to Bp. Chevenix 15 Dec., The several situations, which I have been in, having made me long the plastron of dedications, I am become as callous to flattery, as some people are to abuse. |
c. Applied to an ornamental plaque worn on the breast.
| 1883 D. H. R. Goodale in Harper's Mag. July 242/2 That plastron of steel ornaments is effective. |
2. a. In women's dress, A kind of ornamental front to a bodice, introduced in the latter half of the 19th c.; extended to a loose front of lace, or of some light fabric edged with lace, embroidery, etc.
| 1876 Echo 30 Aug. (Fashions). 1881 Truth 31 Mar. 446/1 The low satin bodice has a plastron embroidered in purple and gold jet. 1883 Cassell's Fam. Mag. Sept. 619/1 Occasionally the waistcoat or plastron is made full. 1886 J. K. Jerome Idle Thoughts (1889) 152, I shall wear my plum-coloured body..with a yellow plastron. 1893 Lady 10 Aug. 146/3 The vest or plastron is of silk covered with lace. 1903 Daily Chron. 28 Mar. 8/4 The stock..is usually made to fasten at the back, so that the front part may be decorative, and is seen, as well, with a little overhanging plastron or wedge-shaped front, or a deep point, edged with open-work or coloured embroidery. 1906 Advertisement, Real Irish crochet lace Plastron..Real Bruges lace Plastron. |
b. In men's dress, A starched shirt-front;
esp. of the kind without pleats.
| 1890 Athenæum 7 June 745/3 The one restraining influence upon the civilized man is the ‘plastron’, otherwise the shirt front of evening dress. 1900 Daily News 24 Mar. 6/4 The light from the lamp..shows a curious and useful reflection on the plastron of the white shirt. |
3. Zool. a. (After Cuvier.) The ventral part of the shell of a tortoise or turtle.
| 1831 tr. Cuvier's Anim. Kingd. IX. 67 The plastron, or breast-plate [of the Order Chelonia] is yellowish and flat, truncated,..and covered with twelve scaly plates. 1835–6 Todd's Cycl. Anat. I. 201/2 This plastron is the sternum, or..the union of several sternums. 1870 Gillmore tr. Figuier's Reptiles & Birds 158 Terrestrial Tortoises are distinguished by their short, oval and convex bodies, covered by carapace and plastron. |
b. Applied to the analogous part in various other animals, as in the extinct labyrinthodon (an amphibian), the glyptodon (allied to the armadillos), certain fossil fishes, and certain existing echinoderms (
e.g. Spatangus): see
quots.| 1854 H. Miller Sch. & Schm. xxiv. (1858) 528 The extraordinary form of Pterichthys..with its arched carapace and flat plastron restored before me. 1888 Rolleston & Jackson Anim. Life 557 As to the interambulacral plates, they become much expanded near the peristome of Spatangidæ... The whole structure constitutes a raised plastron. 1890 Cent. Dict. s.v. Glyptodon, They are all distinguished from the living armadillos..by possessing a ventral shield or plastron. |
c. Ent. [a.
Fr. (F. Brocher 1912, in
Ann. Biol. Lacustre V. 141).] In certain aquatic insects, a type of external gill formed by a patch of cuticle covered with hairs which retain a thin layer of air under water. Also
attrib.| 1947 Thorpe & Crisp in Jrnl. Exper. Biol. XXIV. 227 (title) Studies on plastron respiration. Ibid. 229 The volume of gas in the plastron is negligible. 1959 Southwood & Leston Land & Water Bugs Brit. Is. 367 The air film is self-renewing: oxygen continually diffuses in and out, the whole forming a plastron, or external gill. 1969 R. F. Chapman Insects xxiv. 481 The volume of the plastron is constant and usually small since it does not provide a source of air but acts as a gill. 1976 H. E. Hinton in H. R. Hepburn Insect Integument xxv. 482 In Ptyopteryx..the only diffraction lines are those formed by the plastron on the ventral surface of the abdomen. |
4. Ornith. A coloured area on the breast or belly of a bird, like or likened to a shield.
| 1890 Cent. Dict. cites Coues. 1895 in Syd. Soc. Lex. |
5. Anat. The sternum together with the costal cartilages, the part removed in post-mortem examinations.
| 1890 in Cent. Dict. 1895 in Syd. Soc. Lex. |