parabola -
The explicit drawing of a parallel between two essentially dissimilar things, especially with a moral or didactic purpose. A parable.
Wikipedia
The parabola (from the Greek παραβολή) is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface. Given a point and a corresponding line on the plane, the locus of points in that plane that are equidistant from them is a parabola. The line perpendicular to the directrix and passing through focus (that is the line that splits the parabola through the middle)is called the "axis of symmetry".
OmegaWiki Dictionary
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parabola A conic section generated by the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface.
