callus vs trench

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. 

trench

verb
  • To cut; to form or shape by cutting; to make by incision, hewing, etc. 

  • To dig or cultivate very deeply, usually by digging parallel contiguous trenches in succession, filling each from the next. 

  • To excavate an elongated pit for protection of soldiers and or equipment, usually perpendicular to the line of sight toward the enemy. 

  • To have direction; to aim or tend. 

  • To cut furrows or ditches in. 

  • To excavate an elongated and often narrow pit. 

  • To invade, especially with regard to the rights or the exclusive authority of another; to encroach. 

noun
  • A long, narrow ditch or hole dug in the ground. 

  • A narrow excavation as used in warfare, as a cover for besieging or emplaced forces. 

  • A pit, usually rectangular with smooth walls and floor, excavated during an archaeological investigation. 

  • A trench coat. 

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