radius
/ˈreɪdɪəs; `redɪəs/ n
(pl -dii / -dɪaɪ; -dɪˌaɪ/)
1 (length of a) straight line from the centre of a circle or sphere to any point on its circumference or surface 半径（距离）. =>App 5 见附录 5. =>illus at circle 见circle插图.
2 circular area measured by its radius 用半径度量的圆形面积; 半径范围
Police searched all the woods within a six-mile radius/within a radius of six miles. 警方搜索了在周围六英里以内的树林各处.
3 (anatomy 解) outer shorter bone in the human forearm; corresponding bone in an animal's foreleg or a bird's wing （人与兽的）桡骨; 鸟翼中相当於桡骨的骨. =>illus at skeleton 见skeleton插图. Cf 参看 ulna.