[ 'reɪdɪəs ]
■ noun ( plural radii -dɪʌɪ or ~es )
1》 a straight line from the centre to the circumference of a circle or sphere.
↘a radial line from the focus to any point of a curve.
2》 a specified distance from a centre in all directions: there are plenty of pubs within a two-mile ~.
3》 Anatomy & Zoology a bone of the forearm or forelimb, in humans the thicker and shorter of two.
4》 Zoology a radially symmetric feature in an echinoderm or coelenterate, e.g. an arm of a starfish.
5》 Entomology a main vein in an insect's wing.
■ verb ( ~es , ~ing , ~ed ) [often as adjective ~ed ] make (a corner or edge) rounded.
Origin
C16: from L., lit. 'staff, spoke, ray'.