dilute vs tighten

dilute

verb
  • To become attenuated, thin, or weak. 

  • To cause the value of individual shares or the stake of a shareholder to decrease by increasing the total number of shares. 

  • To weaken, especially by adding a foreign substance. 

  • To make thinner by adding solvent to a solution, especially by adding water. 

adj
  • Of an animal: having a lighter-coloured coat than is usual. 

  • Having a low concentration. 

  • Weak; reduced in strength by dilution; diluted. 

noun
  • An animal having a lighter-coloured coat than is usual. 

tighten

verb
  • To become tighter. 

  • To make tighter. 

  • To raise short-term interest rates. 

  • To make money harder to borrow or obtain. 

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