Circle (Geometry)
A round conic defined by an eccentricity of 0. Also, a favorite shape for the terminally lost.
Conic Section (Math)
The curves that can be formed by slicing up a double-cone—because who wouldn't want to slice up a double-cone.
Directrix (Math)
A line perpendicular to the line of symmetry of a conic. Like the focus, the directrix is used in defining the conic section. The function and the directrix don't get along, and so the graph will always curve away from the directrix.
Eccentricity (Math)
A measure of how weird a conic is, by taking the ratio of the focal distance to the distance to one of the vertices.
Ellipse (Math)
Conic section with two foci within a closed curve. Defined by eccentricities greater than 0, but less than 1. Where would the Universe and especially NASCAR be without them?
Focus (Math)
Not just what we lack at the end of the school year, it is a point related to the curve of a conic section.
Hyperbola (Math)
Conic section with two foci, like the ellipse, but it's not a closed curve. Defined by eccentricities greater than 1. The hyperbola is also bounded by asymptotes.
Parabola
Conic section with one focus. It's defined by an eccentricity equal to 1. Often known by the names "happy and frowny face graphs."
Vertex (Math)
The point where the conic meets the transverse axis or line of symmetry, or the major and minor axes for an ellipse.