1.Definition: a circular region whose area is indicated by the length of its radius

"They located it within a radius of 2 miles"

Category: Places

2.Definition: a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere)

Category: General

3.Definition: support consisting of a radial member of a wheel joining the hub to the rim

Related Noun(s):spoke

Category: Objects

4.Definition: the length of a line segment between the center and circumference of a circle or sphere

Category: General

5.Definition: the outer and slightly shorter of the two bones of the human forearm

Category: General