fossil fuel vs jet fuel

fossil fuel

noun
  • Any fuel derived from hydrocarbon deposits such as coal, petroleum, natural gas and, to some extent, peat; these fuels are non-renewable, and their burning moves carbon from underground into the atmosphere via the greenhouse gas carbon dioxide. 

jet fuel

noun
  • The fuel that powers a jet aircraft. 

  • kerosene 

  • Strong home-brewed alcoholic drink; moonshine. 

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