noun

• (anatomy) The long bone in the forearm, on the side of the thumb.
  "It is also obvious, and proved by experiment, that the rotatory motions observed in the hand proceed from the rotatory motions of the radius."
• (zoology) The lighter bone (or fused portion of bone) in the forelimb of an animal.
• (entomology) One of the major veins of the insect wing, between the subcosta and the media; the vein running along the costal edge of the discal cell.
• (geometry) A line segment between any point of a circle or sphere and its center.
  "Fatima claims to have visited all the bars within a five-mile radius of her Manhattan apartment."

verb

• (transitive) To give a rounded edge to.
  "A comfortable grip is ensured by smoothing the surface of the handle and radiusing the edge."

noun

• (computing) Initialism of Remote Authentication Dial-In User Service.