crux vs substance

crux

noun
  • The basic, central, or essential point or feature. 

  • The critical or transitional moment or issue, a turning point. 

  • The hardest point of a climb. 

  • A puzzle or difficulty. 

  • A cross on a coat of arms. 

substance

noun
  • The essential part of anything; the most vital part. 

  • Physical matter; material. 

  • Material possessions; estate; property; resources. 

  • Hypostasis. 

  • Drugs (illegal narcotics) 

  • Substantiality; solidity; firmness. 

  • A form of matter that has constant chemical composition and characteristic properties. 

verb
  • To give substance to; to make real or substantial. 

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