keystone vs shim

keystone

verb
  • To distort (an image) by projecting it onto a surface at an angle, which for example causes a square to look like a trapezoid. 

  • To double the cost price in order to determine the retail price; to apply a markup of 100%. 

noun
  • A retail price that is double the cost price; a markup of 100%. 

  • A native or resident of the American state of Pennsylvania. 

  • Something on which other things depend for support. 

  • The combination of the shortstop and second baseman. 

  • The top stone of an arch. 

shim

verb
  • To adjust something by using shims. 

  • To fit one or more shims to a piece of machinery. 

  • To adjust the homogeneity of a magnetic field, after the mechanical devices once used for the purpose. 

  • To intercept and modify calls to (an API), usually for compatibility purposes. 

noun
  • A small library that transparently intercepts and modifies calls to an API, usually for compatibility purposes. 

  • A thin piece of material, sometimes tapered, used for alignment or support. 

  • A kind of shallow plow used in tillage to break the ground and clear it of weeds. 

  • A small metal device used to pick open a lock. 

  • A person characterised by both male and female traits, or by ambiguous male-female traits; a hermaphrodite. 

  • A wedge. 

  • A transsexual person, especially a trans woman; (loosely) a drag queen or transvestite. 

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