Pole and polar
（重定向自Polar reciprocation）
![The polar line q to a point Q with respect to a circle of radius r centered on the point O. The point P is the inversion point of Q; the polar is the line through P that is perpendicular to the line containing O, P and Q.](/Images/godic/202502/03/Pole_and_polar.svg4513.png")
![If a point A lies on the polar line q of another point Q, then Q lies on the polar line a of A. More generally, the polars of all the points on the line q must pass through its pole Q.](/Images/godic/202502/03/Conjugate_points_and_lines.svg4513.png")
![Illustration of the duality between points and lines, and the double meaning of](/Images/godic/202502/03/Incidence_poles_polars.svg4513.png")
![Line p is the polar line to point P, l to L and m to M](/Images/godic/202502/03/Pool_poollijn.svg4513.png")
In geometry, the pole and polar are respectively 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.