callus vs chalk

callus

noun
  • A hardened area of the skin (especially on the foot or hand) caused by repeated friction, wear or use. 

  • A shining area on the frons of many species of Tabanomorpha (horse flies and relatives). 

  • The material of repair in fractures of bone; a substance exuded at the site of fracture, which is at first soft or cartilaginous in consistency, but is ultimately converted into true bone and unites the fragments into a single piece. 

  • The new formation over the end of a cutting, before it puts out rootlets. 

verb
  • To form such hardened tissue. 

chalk

noun
  • A white powdery substance used to prevent hands slipping from holds when climbing, or losing grip in weight-lifting or gymnastics, sometimes but not always limestone-chalk, often magnesium carbonate (MgCO3). 

  • A platoon-sized group of airborne soldiers. 

  • The favorite in a sporting event. 

  • The prediction that there will be no upsets, and the favored competitor will win. 

  • A piece of chalk, or nowadays processed compressed gypsum (calcium sulfate, CaSO4), that is used for drawing and for writing on a blackboard (chalkboard). 

  • Tailor's chalk. 

  • A soft, white, powdery limestone (calcium carbonate, CaCO3). 

verb
  • To manure (land) with chalk. 

  • To make white, as if with chalk; to make pale; to bleach. 

  • To record something, as on a blackboard, using chalk. 

  • To apply chalk to anything, such as the tip of a billiard cue. 

  • To use powdered chalk to mark the lines on a playing field. 

  • To record a score or event, as if on a chalkboard. 

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