Pa*rab"o*la (?), n.; pl. Parabolas (#). [NL., fr. Gr. ; -- so called because its axis is parallel to the side of the cone. See Parable, and cf. Parabole.] Geom.
(a) 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.
(b) One of a group of curves
defined by the equation y = axn 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 under Cubical, and Semicubical. The parabolas have
infinite branches, but no rectilineal asymptotes.<
© Webster 1913.