callus vs quit

callus

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. 

verb
  • To form such hardened tissue. 

quit

noun
  • Any of numerous species of small passerine birds native to tropical America. 

adj
  • Released from obligation, penalty, etc; free, clear, or rid. 

verb
  • To leave (a place). 

  • To release from obligation, accusation, penalty, etc.; to absolve; to acquit. 

  • To stop, give up (an activity) (usually + gerund or verbal noun). 

  • To resign from (a job, office, position, etc.). 

  • To close (an application). 

  • To set at rest; to free, as from anything harmful or oppressive; to relieve; to clear; to liberate. 

  • To abandon, renounce (a thing). 

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