‖ chorion
(ˈkɔərɪən)
[a. Gr. χόριον outer membrane of fœtus.]
1. Anat. The outermost membrane enveloping the fœtus before birth. Also attrib., as in chorion-epithelioma = choriocarcinoma; so chorion epitheliomatous adj.
| 1545 T. Raynalde Byrth Man. (1564) xxxiii. 32 The bastyng that is betweene the Matrix and Chorion. 1646 Sir T. Browne Pseud. Ep. iii. vi, In regard the cub comes forth involved in the Chorion, a thick and tough membrane. 1754–64 Smellie Midwif. I. 114 The External coat of the Ovum is the membrane Chorion. 1836 Todd Cycl. Anat. I. 116/1 The chorion of the ova [of the Reptilia] is generally thin or coriaceous, seldom calcified or hard. 1864 F. Hall in Wilson tr. Vishṅu-puráṅa I. 40 Meru was its amnion, and the other mountains were its chorion. 1903 Jrnl. Obstetr. & Gynæcol. IV. 3 The name ‘deciduoma malignum’ is still often used, but the view implied by it is completely abandoned in favour of that of Marchand expressed in the term ‘chorionepithelioma’. 1906 Practitioner Nov. 663 A chorion epithelioma is a tumour which arises, either from the chorion..or from chorionic elements present in teratomata. Ibid., Cases which combine carcinomatous and teratomatous, or chorion epitheliomatous characters have been described. 1964 L. Martin Clinical Endocrinol. (ed. 4) i. 9 Large amounts of chorionic gonadotrophins are present in the urine of patients with chorionepithelioma. |
2. Bot. (See quot.)
| 1816 Keith Phys. Bot. iv. viii. §2 The Chorion, so named by Malpighi, is the soft and pulpy substance of the primitive nucleus of the seed. |
3. Anat. The cutis vera or true skin; = corium.
| 1831 R. Knox Cloquet's Anat. 333 They.. terminate in the chorion of the skin. 1845 Todd & Bowman Phys. Anat. I. 434 The chorion, or cutis, is tough. |
† 4. = Choroid tunic. Obs.
| 1650 Bulwer Anthropomet. 73 The thin membrane Chorion, the first that covereth the Optique sinew. |