radius
noun [ C ] uk/ˈreɪ.di.əs/ us/ˈreɪ.di.əs/ radii
(DISTANCE)
（圆或球体的）半径，半径长度
(the length of) a straight line joining the centre of a circle to its edge or the centre of a sphere to its surface
The radius of this wheel is 30 cm.. 这个轮子的半径是30厘米。
This wheel has a radius of 30 cm. 这个轮子的半径是30厘米。
半径距离;半径范围;周围
a distance from a central point
The station, shopping centre and school lie within a one-mile radius of the house. 车站、购物中心和学校都在距这所房子1英里的范围之内。
(BONE)
anatomy specialized桡骨
the thicker of the two bones in the lower arm