callus vs grate

callus

verb
  • To form such hardened tissue. 

noun
  • 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. 

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

grate

verb
  • To shred (things, usually foodstuffs), by rubbing across a grater. 

  • To annoy. 

  • To get on one's nerves; to irritate, annoy. 

  • To make an unpleasant rasping sound, often as the result of rubbing against something. 

  • To furnish with grates; to protect with a grating or crossbars. 

noun
  • A horizontal metal grill through which water, ash, or small objects can fall, while larger objects cannot. 

  • A frame or bed, or kind of basket, of iron bars, for holding fuel while burning. 

  • A grapper, a metal ring on a lance behind the grip. 

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