- Parabolic mirror
- 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]
The Collaborative International Dictionary of English. 2000.