coke vs rock cocaine

coke

noun
  • Cocaine. 

  • Solid residue from roasting coal in a coke oven; used principally as a fuel and in the production of steel and formerly as a domestic fuel. 

verb
  • To add deleterious carbon deposits as a byproduct of combustion. 

  • To produce coke from coal. 

  • To turn into coke. 

rock cocaine

noun
  • The off-white, crystal-like form of crack cocaine. 

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