◙ (pl. radii -dɪʌɪ 或者 radiuses) 1. a straight line from the centre to the circumference of a circle or sphere • 半径 a radial line from the focus to any point of a curve • 辐射距离 the length of the radius of a circle or sphere • 半径距离 a specified distance from a centre in all directions • （指明的）半径范围 »there are plenty of local pubs within a two-mile radius. 在两英里范围内有许多本地酒馆。 2. [Anatomy] the thicker and shorter of the two bones in the human forearm • [剖] 桡骨。 --› compareulna [Zoology] the corresponding bone in a vertebrate's foreleg or a bird's wing • [动] （脊椎动物前肢或鸟翅的）桡骨 [Zoology] (in an echinoderm or coelenterate) any of the primary axes of radial symmetry • [动] （棘皮动物或腔肠动物的）辐射对称轴 [Entomology] any of the main veins in an insect's wing • [昆] 径脉 ◙ (radiused, radiusing) 1. [with obj.] [often as adj. radiused] give a rounded form to (a corner or edge) • 使（角，边缘）成弧形
【语源】
1. late 16th cent. (in sense 2): from Latin, literally staff, spoke, ray'