mountainous vs pyramidic

mountainous

adj
  • Having many mountains; characterized by mountains; of the nature of a mountain; rough (terrain); rocky. 

  • Very difficult. 

  • Resembling a mountain, especially in size; huge; towering. 

pyramidic

adj
  • Of or pertaining to a pyramid; having the form or imposing presence of a pyramid; pyramidal. 

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