'Parabolic conoid' definitions:

Definition of 'Parabolic conoid'

From: GCIDE
  • Parabolic \Par`a*bol"ic\, Parabolical \Par`a*bol"ic*al\, a. [Gr. paraboliko`s figurative: cf. F. parabolique. See Parable.] [1913 Webster]
  • 1. Of the nature of a parable; expressed by a parable or figure; allegorical; as, parabolical instruction. [1913 Webster]
  • 2. [From Parabola.] (Geom.) (a) Having the form or nature of a parabola; pertaining to, or resembling, a parabola; as, a parabolic curve. (b) Having a form like that generated by the revolution of a parabola, or by a line that moves on a parabola as a directing curve; as, a parabolic conoid; a parabolic reflector; a parabolic antenna. [1913 Webster +PJC]
  • Parabolic conoid, a paraboloid; a conoid whose directing curve is a parabola. See Conoid.
  • Parabolic mirror (Opt.), a mirror having a paraboloidal surface which gives for parallel rays (as those from very distant objects) images free from aberration. It is used in reflecting telescopes.
  • Parabolic spindle, the solid generated by revolving the portion of a parabola cut off by a line drawn at right angles to the axis of the curve, about that line as an axis.
  • Parabolic spiral, a spiral curve conceived to be formed by the periphery of a semiparabola when its axis is wrapped about a circle; also, any other spiral curve having an analogy to the parabola. [1913 Webster]