a. and sb. Also 6 -ike, -yke, 7– -ique, 7–8 ick. [mod. ad. Gr. κωνικ-ός cone-shaped, f. κῶνος cone: see -IC. Cf. F. conique (not in Cotgr., 1611).]
A. adj. 1. Having the form of a cone; cone-shaped, CONICAL.
1614. Selden, Titles Hon., 150. [Heraclius’ Crown] being of gold, and raisd with variety of conique plates.
1647. H. More, Song of Soul, I. III. vi. (R.). An anvile form’d in conick wise.
1706. Lond. Gaz., No. 4292/3. Letters Patents for Enlightening the Suburbs of London … by new invented Lights or Lamps, called Conic-Lamps.
1772–84. Cook, Voy. (1790), IV. 1226. A succession of conic hills.
1854. Woodward, Mollusca, II. 318. Shell oblong; right valve with a curved, conic tooth in front of the … cartilage-pit.
1870. Hooker, Stud. Flora, 387. Styles 3, conic, persistent.
2. Of or pertaining to a cone. Conic section: a figure formed by the section of a right circular cone by a plane; a plane curve of the second degree.
If the inclination of the cutting plane to the axis of the cone be greater than that of the edge of the cone, the section is an ELLIPSE (with the circle as a particular case when the plane is perpendicular to the axis); if less, a HYPERBOLA; if the plane be parallel to the edge, a PARABOLA. (The pair of intersecting straight lines formed by a section through the vertex—strictly a particular case of the hyperbola—is not usually reckoned as a conic section.)
1570. Dee, Math. Pref., 31. Our fourth Pyramidall, or Conike line.
1664. Power, Exp. Philos., III. 187. The Forming of Conick Sections in Dioptricks … accounted as insuperable difficulties.
1706. Phillips (ed. Kersey), Conical … as Conick Sections, i. e. the three Sections or Divisions of a Cone, call’d Ellipsis, Hyperbola and Parabola.
1714. Barrow’s Euclid, 517. This method don’t suppose the conic surface … to consist of as many parallel circumferences perpetually increasing from the vertex, or decreasing from the base.
1807. Hutton, Course Math., II. 93. There arise five different figures or sections, namely, a triangle, a circle, an ellipsis, an hyperbola, and a parabola: the three last of which only are peculiarly called Conic Sections.
1866. Proctor, Hand-bk. Stars, 18. The projection is a closed curve, which (being a conic section) must be either a circle or an ellipse.
3. Comb., as conic-billed.
1846. McCulloch, Acc. Brit. Empire (1854), I. 125. Tribe Conirostres. Conic-billed Birds.
B. sb.
1. pl. Conics: that branch of Geometry that treats of the cone and the figures formed by plane sections of it. (Now regarded as the pl. of 2, as if = conic sections.)
1571. Digges, Pantom., Pref. A ij. A number of rules and preceptes, gathered out of Euclide, Archimedes and Appolonius Pergeus his Conykes.
c. 1850. Rudim. Navig. (Weale), 109. The science of Conics is of the highest utility.
Mod. Analytical and Geometrical Conics.
2. A conic section: see A. 2.
1879. Salmon, Conic Sections, xiiii. (ed. 6), 226. Two conics cannot have more than four points common.
1885. Leudesdorf, Cremona’s Proj. Geom., 15. The curve which is homological with a circle is a conic.
