Noun
circumcircle (plural circumcircles)
(geometry) A circle that passes through every vertex of a given triangle (or other polygon where possible)
As mentioned above, every triangle has a unique circumcircle, a circle passing through all three vertices, whose center is the intersection of the perpendicular bisectors of the triangle's sides. Source: Internet
In this example the size of the vertex figure was chosen so that its circumcircle lies on the intersphere of the cuboctahedron, which also becomes the intersphere of the dual rhombic dodecahedron. Source: Internet
Tsukerman's converse to Lambert's theorem states that, given three lines that bound a triangle, if two of the lines are tangent to a parabola whose focus lies on the circumcircle of the triangle, then the third line is also tangent to the parabola. Source: Internet
The product of two sides of a triangle equals the altitude to the third side times the diameter of the circumcircle: Altshiller-Court, Nathan, College Geometry, Dover, 2007. Source: Internet