| 释义 |
vertex|ˈvɜːtɛks|
Pl. vertices |ˈvɜːtɪsiːz|; also vertexes.
[a. L. vertex whirl, whirlpool, vortex; crown of the head, highest point, summit, etc., f. vertĕre to turn. Cf. vertice.]
1. a. Geom. The point opposite to the base of a (plane or solid) figure; the point in a curve or surface at which the axis meets it; an angular point, as of a triangle or polygon.
1570Dee Math. Pref. C ij, From the vertex, to the Circumference of the base of the Cone. 1571Digges Pantom. iv. xxv. Hh ij, A transfigured Icosaedron may be resolued into 12 Pentagonal and 20 hexagonal Pyramides, concurring with their toppes or vertices all in the centers of this transformed body. a1608Dee Relat. Spir. i. (1659) 355, 4 Triangles or rather Cones, of water, whose vertices rest cut off (as it were) by the middle stream of water. 1672Boyle Virtues Gems 12 So as to make six triangles, that terminated like those of a Pyramid in a Vertex. 1715Desaguliers Fires Impr. 13 Two half Parabolas's whose Vertex's are C c. 1743Emerson Fluxions 150 In the vertices of Curves, where they cut the Abscissa at right angles. 1840Lardner Geom. ii. 17 These lines are called the sides of the angle, and the point C where the sides unite, is called its vertex. 1860Tyndall Glac. i. vii. 54 Along the two sides of a triangle, the vertex of which was near the centre of the glacier. 1882Minchin Unipl. Kinemat. 12 The parallelogram must now be jointed at its four vertices.
b. Optics. (See quots.)
1704J. Harris Lex. Techn. I, Vertex of a Glass (in Opticks) is the same with its Pole. 1797Encycl. Brit. (ed. 3) XIII. 288 Draw the ray RC through the centre, cutting the [spherical] surface in the point V, which we shall denominate the vertex, while RC is called the axis. 1803J. Imison Sci. & Art I. 348 To find the vertex or centre of a lens. 1867J. Hogg Microsc. i. ii. 18 The point where the axis cuts the surface is called the vertex of the lens.
c. Astr. (See quot.)
1876G. F. Chambers Astron. 922 Vertex.., a term used to designate that point in the limb of the Sun, the Moon, or of a planet, intersected by a circle passing through the zenith and the centre of the body.
d. Math. A junction of two or more lines in a network or graph (graph n.1 1); = node n. 7 b.
1931Proc. Nat. Acad. Sci. XVII. 125 A graph G is composed of two sets of symbols: vertices, a, b,{ddd}, f, and arcs, α(ab).., β(ac),{ddd}, δ(ef). 1942G. T. Whyburn Analytic Topol. x. 182 Such a decomposition of a graph A into vertices and edges is called a subdivision of A. 1975I. Stewart Concepts Mod. Math. xi. 160 A network has two main parts: (i) a set N, whose elements are called nodes or vertices, (ii) a way of specifying when two vertices are joined together. 1979Sci. Amer. May 98/3 Alpha-actinin was localized primarily at the vertexes of the network and tropomyosin was localized along the short fibers connecting the vertexes.
2. The point in the heavens vertically overhead, or directly above a given place; the zenith. latitude or meridian of vertex (see quot. c 1850).
1646Sir T. Browne Pseud. Ep. ii. ii. 62 The true meridian is a major circle passing through the poles of the world, and the Zenith or Vertex of any place. 1665Sir T. Herbert Trav. (1677) 5 These sorts of people freeze within the polar circles,..the Pole being their vertex, and the æquator..their direct Horizon. Ibid. 39 The heat..when the Sun comes to the Vertex, is much more intense..than it is about the Polar Circles. 1715tr. Gregory's Astron. (1726) I. 346 When the Phænomenon..is in XDZ the common Azimuth..of the two places on the Earth pitch'd upon for this purpose, whose Vertices are X and Z. 1748Anson's Voy. ii. v. 182 The Sun was within about three degrees of the vertex. c1850Rudim. Navig. (Weale) 54 Either of these points is called the vertex of the great circle to which it belongs; the arc intercepted between the vertex and the equator is the latitude of vertex; the meridian that passes through the vertex is the meridian of vertex. 1867Smyth Sailor's Word-bk., Vertex, the zenith, the point overhead.
3. a. Anat. (and Zool.). The crown or top of the head; esp. in man, the part lying between the occiput and the sinciput. vertex presentation, a presentation (presentation 8 b) in which the vertex of the fœtus lies nearest to the cervix as labour begins.
[1615Crooke Body Man vii. ii. (1631) 434 The middle part of the scalpe..is gibbous or round;..the Latins call it Vertex, because in that place the haires runne round in a ring as waters doe in a whirle-poole.] 1638A. Read Man. Anat. iii. i. 389 Vertex, the crown, that which is betweene the former two, somewhat arched. 1680S. Haworth Disc. Conc. Man 115 The middle Part between these which is Gibbose is called Vertex. 1754–64Smellie Midwif. I. 86 [In child-birth] the crown or vertex is the first part that is pressed down, because..the bones at that part of the skull make the least resistance. 1771Encycl. Brit. II. 226/2 The [Columba] turbita, with..a short bill, and a plain vertex. 1840E. Wilson Anat. Vade M. (1842) 43 The skull..is divisible into four regions,—a superior region or vertex, a lateral region, an inferior, and an interior region. 1841F. H. Ramsbotham Princ. & Pract. Obstetr. Med. 135 (heading) Comparative frequency of the various modes of vertex presentation. 1873Coues Birds N.W. (1874) 281 That the young males have more or less of the vertex red or yellow, instead of an occipital crescent of scarlet. 1888P. L. Sclater Argentine Ornith. I. 137 Vertex more or less tinged with rufous. 1899Allbutt's Syst. Med. VII. 482 In these vertex cases [of tuberculous meningitis]. Ibid. VIII. 8 The forceps was employed fifteen times in vertex presentations. 1974Encycl. Brit. Micropædia VIII. 195/2 In vertex presentations the head of the fetus most commonly faces to the right and slightly to the rear. This position is said to be the most usual one, because the fetus is thus best accommodated to the shape of the uterus.
b. Ent. (See quots.)
1826Kirby & Sp. Entomol. III. 365 Vertex, the horizontal part of the Facies, next the front, that lies behind the eyes and between the temples. Ibid. 487 In Blatta and some other Orthoptera the posterior angle of the head is the vertex. 1861–2Le Conte Classif. Coleoptera N. Amer. i. Introd. p. x, The upper surface is divided into regions, the back part being called the occiput, the middle the vertex, and the anterior the front. 1897W. F. Kirby in Mary Kingsley W. Africa 719 Trichomera insignata... Face nearly smooth, shining black below the vertex.
4. The top, summit, or highest point of something, esp. a hill or structure; the crown of an arch. † Also, a high piece of land, an eminence (obs.).
1641R. Brooke Eng. Episc. 21, I am neere the Apex of this question, which yet (Pernassus-like) hath a double Vertex, a twofold toppe. 1691Ray Creation i. (1692) 203 The great diversity of Soyls that are found there, every Vertex, or Eminency, almost affording new kinds. 1762Falconer Shipwr. iii. 243 Its [an altar's] vertex thirty cubits from the ground. 1770Pennant Brit. Zool. (1777) IV. 142 Patella vulgata... Vertex pretty near the centre. 1811Pinkerton Petralogy II. 338, I was not more than a hundred and fifty paces distant from the vertex of the cone. 1827Gentl. Mag. XCVII. ii. 9 A conical dome, on the vertex of which is a gilt cross. 1879Cassell's Techn. Educ. I. 197/1 The highest point in the intrados is called the vertex or crown.
fig.1865Mozley Mirac. vi. 130 The question whether man is or is not the vertex of nature. |