Usually applies to a triangle, but also to regular polygons.

The point where the three perpendicular bisectors of the sides of a triangle meet. Also, the center of the circumcircle. One of a triangle's points of concurrency.

For more see Circumcenter of a triangle.

Pages referring to 'circumcenter'

Circumcircle of a triangle. Definition and properties with interactive applet.
Animation showing that in any triangle, the centroid, circumcenter and orthocenter are always collinear - they always lie on a straight line, called the Euler line.
This page shows how to construct (draw) the circumcenter of a triangle with compass and straightedge or ruler. The circumcenter of a triangle is the point where the perpendicular bisectors of the sides intersect. It is also the center of the circumcircle, the circle that passes through all three vertices of the triangle. A Euclidean construction.
An overview of the various centers of a triangle
Definition and properties of the circumcenter of a triangle