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Par·a·bol·ic Par·a·bol·ic·al a.

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

2. 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.

**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.

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