radius

A line segment that joins the center of a circle with any point on its circumference.

A line segment that joins the center of a sphere with any point on its surface.

A line segment that joins the center of a regular polygon with any of its vertices.

The length of any such line segment.

A circular area measured by a given radius.

A bounded range of effective activity or influence.

A radial part or structure, such as a mechanically pivoted arm or the spoke of a wheel.

A long, prismatic, slightly curved bone in humans, the shorter and thicker of the two forearm bones, located on the lateral side of the ulna.