Why are circles ellipse parabolas and hyperbolas called conic sections?

Circles, parabolas, ellipses,and hyperbolas are called conic sections because you can get those shapes by placing two cones - one on top of the other - with only the tip touching, and then you cut those cones by a plane. When you move that plane around you get different shapes.

If you want to see an illustration of these properties, click on the link below on the related links section.