R vs radius

R

noun
  • radius 

  • rex (“king”) or regina (“queen”); the initial by which a British monarch signs documents after his or her name 

  • the Crown, the government of a monarchy (abbreviating rex (“king”) or regina (“queen”)) 

  • rook 

  • Thursday 

  • Republican 

  • ring 

  • runs, the statistic reporting the number of runs scored by a player 

adj
  • right (as opposed to left) 

  • reverse 

  • restricted 

character
  • The eighteenth letter of the English alphabet, called ar and written in the Latin script. 

name
  • In the context of the documentary hypothesis, the Redactor(s) who compiled and edited the Torah. 

radius

noun
  • The length of this line segment. 

  • The lighter bone (or fused portion of bone) in the forelimb of an animal. 

  • A line segment between any point of a circle or sphere and its center. 

  • The long bone in the forearm, on the side of the thumb. 

  • 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. 

  • Anything resembling a radius, such as the spoke of a wheel, the movable arm of a sextant, or one of the radiating lines of a spider's web. 

How often have the words R and radius occurred in a corpus of books? (source: Google Ngram Viewer )