Pa·rab·o·la n.; pl. Parabolas   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 = See under Cubical, and Semicubical.  The parabolas have infinite branches, but no rectilineal asymptotes.

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From: Webster's Revised Unabridged Dictionary (1913)

 Cu·bic Cu·bic·al a.
 1. Having the form or properties of a cube; contained, or capable of being contained, in a cube.
 2. Crystallog. Isometric or monometric; as, cubic cleavage. See Crystallization.
 Cubic equation, an equation in which the highest power of the unknown quantity is a cube.
 Cubic foot, a volume equivalent to a cubical solid which measures a foot in each of its dimensions.
 Cubic number, a number produced by multiplying a number into itself, and that product again by the same number. See Cube.
 Cubical parabola Geom., two curves of the third degree, one plane, and one on space of three dimensions.

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