placentaladj.n.
/pləˈsɛntl/, U.S. /pləˈsɛn(t)l/ A. adj.
1. Of or relating to a placenta or placentas.
a. Anatomy and Zoology.
ΘΚΠ
the world > life > biology > biological processes > procreation or reproduction > embryo or fetus > membranes, etc., of embryo or fetus > [adjective] > placenta
placentary1734
placental1785
diffuse1856
aplacental1859
zonary1881
1785 J. Aitken Princ. Midwifery (ed. 2) i. 28 The placental vessels and their lobes are connected by cellular matter, which pretty completely covers, as with a lamina, the uterine surface of it.
1808 J. Barclay Muscular Motions 367 From a change of function, placental blood is no longer returned to the liver.
1876 J. S. Bristowe Treat. Theory & Pract. Med. ii. i. 262 The raw surfaces of wounds or of the placental area.
1893 New Sydenham Soc. Lexicon P[eriod], placental, the time occupied in the expulsion of the placenta.
1963 A. Smith Throw out Two Hands (1966) xvii. 162 Some jackals had come nearer, but..they only wanted the placental afterbirth.
1996 Pulse 20 Apr. 42/6 In view of recent work on placental function and diet, the food intake itself needs closer inspection before we can optimise our advice.
b. Botany.
ΘΚΠ
the world > plants > part of plant > reproductive part(s) > flower or part containing reproductive organs > [adjective] > having or relating to parts > of or having stamens or pistils > of or having style, pistil, or female parts > of or relating to or having a placenta
placental1791
placentary1839
placentiferous1878
placentigerous1890
1791 E. Darwin Bot. Garden: Pt. I i. 194 The lobes are reservoirs of prepared nutriment for the young seed, which is absorbed by its placental vessels.
1857 A. Henfrey Elem. Course Bot. §227 In Leguminosæ the double placental base is so narrow that the ovules alternate with one another.
1870 J. D. Hooker Student's Flora Brit. Islands 259 Ovule..flanked by a column of placental tissue.
1951 G. H. M. Lawrence Taxon. Vascular Plants i. iv. 75 In some plants..the cells of the placental area proliferate and form a prominent tissue mass.
2000 Bot. Rev. (Nexis) 1 Apr. 155 Whether the ovules are really inserted in distinct vertical rows or scattered over the placental surface is not sufficiently known.
2. Zoology. Designating a mammal characterized by the development of a true placenta in the female; eutherian, as distinct from monotreme or marsupial.
ΘΚΠ
the world > animals > mammals > [adjective] > of parts of > having a placenta
placentiferous1667
placental1837
placentigerous1890
1837 R. Owen in Philos. Trans. (Royal Soc.) 127 89 In order to obtain satisfactory proof of the difference in the structure of the brain in the marsupial and placental quadruped, I dissected..the brains of a Wombat and Beaver.
1871 C. Darwin Descent of Man I. vi. 202 The Marsupials stand..below the placental mammals.
1957 L. Eiseley Immense Journey 8 In the Paleocene occurred the first great radiation of the placental mammals.
1985 E. H. Colbert Wandering Lands & Animals (new ed.) x. 254 The marsupial borhyaenids quickly succumbed to competition from the obviously more intelligent placental carnivores and became extinct.
3. Obstetrics. Designating the sound thought to be caused by blood flowing through the placenta, heard in auscultation during the later months of pregnancy; esp. in placental souffle, placental sound.
ΚΠ
1843 R. J. Graves Syst. Clin. Med. vii. 84 (note) No one who has ever heard the placental soufflet.
1855 J. King Amer. Eclectic Obstretr. 103 The audible signs, are those detected by the ear, with or without the aid of the stethoscope, among which is, the placental sound, or bruit de souffle.
1855 J. King Amer. Eclectic Obstetr. 679 No placental murmur or sounds of fetal heart heard.
1900 W. A. N. Dorland Amer. Illustr. Med. Dict. 611/1 Placental souffle, a souffle supposed to be produced by the blood-current in the placenta.
1967 Jrnl. Amer. Med. Assoc. 199 327/2 The placental sound can frequently be heard..if the implantation is on the anterior surface of the uterus.
1994 Oxf. Textbk. Surg. II. 1424/2 A placental souffle, identified with a portable Doppler ultrasound transducer, is also suggestive of pregnancy, while detection of fetal heart sounds is diagnostic.
B. n.
Zoology. A placental mammal, a eutherian.
ΘΚΠ
the world > animals > mammals > group Placentalia > [noun] > member of
placental1841
monodelph1842
Deciduata1866
monodelphian1873
deciduate1880
eutherian1880
placentary1890
1841 R. Owen in Todd's Cycl. Anat. & Physiol. III. 299/2 The stomach is relatively much more capacious in the carnivorous Marsupials than in the carnivorous Placentals.
1863 C. Darwin Let. 6 Mar. in Corr. (1999) XI. 209 A person might say that you thought that bats & rodents were not placentals.
1897 Appletons' Pop. Sci. Monthly Nov. 17 The marsupials..have been gradually supplanted by the more highly organized placentals.
1950 J. Z. Young Life of Vertebr. xxi. 545 All the eutherians (placentals) have been derived from small, perhaps nocturnal, insectivorous or omnivorous animals.
1988 Nature 12 May 113/1 But in both areas the mammals were all placentals and marsupials, and comparable similarity has been more or less assumed for earlier times.
This entry has been updated (OED Third Edition, June 2006; most recently modified version published online June 2022).
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adj.n.1785