parabolic, a. and n.
(pærəˈbɒlɪk)
[ad. late L. parabolicus, a. late Gr. παραβολικός figurative (Clemens Alex.), f. παραβολή parable; in mod. use referred also to parabola; cf. F. parabolique (14th c. in Littré).]
A. adj.
1. a. Of, pertaining to, or of the nature of a parable; ‘expressed by parable’ (J.).
| c 1449 Pecock Repr. (1860) II. 533 Signified bi likenes in parabolik speche. 1669 Gale Crt. Gentiles i. i. ii. 11 Traditions; which he wraps up in..parabolic..notions. 1804 Collins Scripscrap 96 And through each parabolic tract, Pursue the trail of moral fact. 1882 A. B. Bruce (title) The Parabolic Teaching of Christ, a systematic and critical study of the parables of Our Lord. |
b. Of or pertaining to parabole; metaphorical.
| 1696 Whiston Th. Earth (1722) 66 Resolving the whole into a Popular, Moral, or Parabolick Sense. 1878 G. D. Boardman Creative Week 20 (Cent.) Creation..transcends all experience... Hence all the words describing Creation must, in the very nature of the case, be figurative or parabolic. |
2. Geom. Of the form of, or resembling, a parabola; of which the section is a parabola; also, having relation to the parabola.
parabolic asymptote: see quot. 1788. parabolic branch (of a curve): a branch which, like the parabola, extends to infinity without approaching an asymptote (opp. to hyperbolic). parabolic conoid: a conoid of parabolic section, a paraboloid of revolution. parabolic point: a point on a surface at which the curvature is cylindrical, the indicatrix thus being two parallel straight lines, i.e. a degenerate parabola. parabolic pyramidoid: see pyramidoid. parabolic reflector: a reflector, usually of polished metal, made in the form of a paraboloid of circular section, so as to reflect parallel rays to a focus, or reflect in parallel lines the rays of a lamp placed at the focus. parabolic space: (a) the space between an arc of a parabola and its ordinate; (b) name given by Klein to a space, of any number of dimensions, of zero curvature, as ordinary or Euclidean space (see hyperbolic 2 b, quot. 1872–3). parabolic spindle: a figure formed by the revolution of an arc of a parabola about its (double) ordinate. parabolic spiral = helicoid parabola: see helicoid.
| 1702 Ralphson Math. Dict., Paraboloid..otherwise called a Parabolick Conoid. 1704 Parabolic spiral [see helicoid A. 1]. 1706 Phillips, Parabolick Space, is the Area..between the Curve..of the Parabola and any entire Ordinate. Ibid., Parabolick Spindle. 1748 Hartley Observ. Man i. iii. 357 The parabolic Area equal to 2/3 of the circumscribing Parallelogram. 1788 Chambers Cycl. (ed. Rees), Parabolic asymptote,..a parabolic line approaching to a curve, so that..by producing both indefinitely, their distance from each other becomes less than any given line. 1822 J. Imison Sc. & Art I. 19 The resistance of the air and other causes occasion projected bodies to deviate considerably from the parabolic curve. 1831 Brewster Optics xxxviii. §185. 323 Parabolic reflectors made of metal. 1842 Penny Cycl. XXIII. 304/1 The elliptic, parabolic, and hyperbolic cylinders are perfectly distinct. 1869 Boutell Arms & Arm. xi. (1874) 225 [They] made experiments with parabolic shot or bombs. 1872 Proctor Ess. Astron. iii. 40 Comets which sweep round the sun in parabolic or hyperbolic orbits. 1955 Sci. Amer. Mar. 38/1 A parabolic ‘dish’, either solid or made of a wire screen, reflects incoming radio waves to a focal point, where a small dipole or rod picks up the energy. 1960 Practical Wireless XXXVI. 391/1 The radio telescope, a parabolic mirror of 83ft diameter..scans the sky. 1962 A. Nisbett Technique Sound Studio i. 23 An assembly consisting of a cardioid or omnidirectional microphone fitted at the focus of a parabolic reflector is also strongly directional. 1965 P. Wayre Wind in Reeds vi. 74 Separate E.M.I. recording equipment, including..a microphone which could be used in conjunction with a parabolic reflector. 1969 Times 4 Feb. 13/3 He seems to have recorded pulses of energy by means of a large array of parabolic mirrors. 1977 P. Hill Fanatics 38 Could we have a parabolic microphone in the control flat? |
B. n.
† 1. Geom. A parabolic figure; a parabola or paraboloid. Obs. rare.
| 1657 W. Rand tr. Gassendi's Life Peiresc ii. 100 Whether those..are the portions of Globes or of Parabolicks, or other figures, is truely hard to judge. 1807 Southey Espriella's Lett. II. 137 They were talking of parabolics and elliptics. |
2. A parabolic expression, a metaphor. nonce-use.
| 1829 Blackw. Mag. XXVI. 736 The grandeur of the house was above all parabolics. |