| parabola | Origin: NL, fr. Gr.; so called because its axis is parallel to the side of the cone. See Parable, and cf. Parabole. <geometry> A kind of curve; one of the conic sections formed by the intersection of the surface of a cone with a plane parallel to one of its sides. It is a curve, any point of which is equally distant from a fixed point, called the focus, and a fixed straight line, called the directrix. See Focus. One of a group of curves defined by the equation y = ax^n where n is a positive whole number or a positive fraction. For the cubical parabola n = 3; for the semicubical parabola n = 3/2. See Cubical, and Semicubical. The parabolas have infinite branches, but no rectilineal asymptotes. Source: Websters Dictionary (01 Mar 1998) |
|---|