| support consisting of a radial member of a wheel joining the hub to the rim | the length of a straight line passing through the center of a circle and connecting two points on the circumference |
| the length of a line segment between the center and circumference of a circle or sphere | a straight line connecting the center of a circle with two points on its perimeter (or the center of a sphere with two points on its surface) |
| the outer and slightly shorter of the two bones of the human forearm | |
| a circular region whose area is indicated by the length of its radius | |
| a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere) | |