Pole (geometry)

Pole (geometry)

In geometry, the terms pole and polar are used to describe a point and a line that have a unique reciprocal relationship with respect to a given conic section. If the point lies on the conic section, its polar is the tangent line to the conic section at that point.

For a given circle, reciprocation in a circle means to transform each point in the plane into its polar line and each line in the plane into its pole.