esker vs inclination

esker

noun
  • A long, narrow, sinuous ridge created by deposits from a stream running beneath a glacier. 

inclination

noun
  • A slant or slope. 

  • A tendency. 

  • The angle of intersection of a reference plane 

  • A physical tilt or bend. 

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