a plane curve formed by the intersection of a right circular cone and a plane parallel to an element of the curve
source: WordNet 3.0
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.
