radius /'reidias; 'redias/ n (pl -dii) /-dial; -di,ai/ 1 (length of a) straight line from the centre of a circle or sphere to any point on the circumference or surface, 半徑。 → the illus at circle. 參看 circle 之插圖。 2 circular area measured by its ~: 以半徑度量之圓形面積： The police searched all the fields and woods within a ~ of two miles. 警方搜查半徑兩英里范圍內(nèi)所有的田野和森林。 3 (anat) outer of the two bones in the forearm. (解剖)橈骨。 → the illus at skeleton. 參看 skeleton 之插圖。