Category:Parabolic

Par`a*bol"ic, par`a*bol"ic*al, a. Etym: [gr. parabolique. See Parable.]

1. Of the nature of a parable; expressed by a parable or figure; Allegorical; as, parabolical instruction.

2. Etym: [from parabola.] (geom.) (a) having the form or nature of a parabola; pertaining to, or Resembling, a parabola; as, a parabolic curve. (b) generated by the revolution of a parabola, or by a line that Moves on a parabola as a directing curve; as, a parabolic conoid. 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.