cubit vs radius

cubit

noun
  • The distance from the elbow to the tip of the middle finger used as an informal unit of length. 

  • Any of various units of length approximating this distance, usually around 35–60 cm. 

radius

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

  • 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. 

  • 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. 

  • The length of this line segment. 

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