bitumen vs macadam

bitumen

noun
  • Roads sealed with bitumen, as opposed to dirt roads. 

  • Any one of the natural hydrocarbons, including the hard, solid, brittle varieties called asphalt, the semisolid maltha and mineral tars, the oily petrolea, and even the light, volatile naphthas. 

  • A sticky, black, highly viscous liquid or semi-solid form of petroleum, burning with a bright flame. It occurs as an abundant natural product in many places, as on the shores of the Dead and Caspian Seas. It is used in cements, in the construction of pavements, etc.; Mineral pitch. 

  • Canadian deposits of extremely heavy crude oil. 

verb
  • To cover or fill with bitumen. 

macadam

noun
  • The surface of a road consisting of layers of crushed stone (usually tar-coated for modern traffic). 

verb
  • To cover or surface with macadam. 

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