definition of
radius

[1] #1 radius n. [r] the length of a line segment between the center and circumference of a circle or sphere. wn

[2] #2 radius n. a straight line from the center to the perimeter of a circle (or from the center to the surface of a sphere). wn

[3] #3 radius n. a circular region whose area is indicated by the length of its radius; "they located it within a radius of 2 miles". wn

[4] #4 radius n. the outer and slightly shorter of the two bones of the human forearm. wn

[5] #5 radius n. [spoke, wheel spoke] support consisting of a radial member of a wheel joining the hub to the rim. wn