Circumradius

Part of speech: noun

Definitions

1. The length from the center of a polygon to one of its vertices identifies the radius associated with the circumcircle, which encompasses all vertices of said polygon
2. A measurement indicating the distance from a polygon’s center to a vertex that represents the radius of the circle passing through all vertices of the polygon
3. The distance measured from the center of a polygon to any of its vertices, representing the radius of the circle that passes through all those vertices

Etymology: Circumradius is a plain technical compound: the prefix "circum-" (Latin for "around") joined to "radius" (Latin for "ray" or "spoke of a wheel"). Together they name the radius of a circle drawn around a polygon, passing through all its corners. The word is a mathematical coinage built from classical parts rather than a term that circulated in everyday speech. The "radius" half has a striking history of its own. In Latin it meant a rod or spoke, and it was used for the ray of a wheel and for a staff used in measuring. Its link to the circle comes from that image of a line running out from a centre, like a spoke. The prefix "circum-" shares its root with "circus," which in Latin meant a ring or circular course, and that circular sense is what makes the word apt for a circle surrounding a shape.