conic, a. and n.
(ˈkɒnɪk)
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 Handbk. 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 M{supc}Culloch Acc. Brit. Empire (1854) I. 125 Tribe Conirostres. Conic-billed Birds. |
B. n.
1. pl. conics: that branch of Geometry which 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 C. Leudesdorf Cremona's Proj. Geom. 15 The curve which is homological with a circle is a conic. |