elemental vs liminal

elemental

adj
  • Basic, fundamental or elementary. 

  • Of, or relating to a force of nature, especially to severe atmospheric conditions. 

  • Of, relating to, or being an element (as opposed to a compound). 

  • Of the ancient supposed elements of earth, air, fire and water. 

noun
  • A creature (usually a spirit) that is attuned with, or composed of, one of the classical elements: air, earth, fire and water or variations of them like ice, lightning, etc. They sometimes have unique proper names and sometimes are referred to as Air, Earth, Fire, or Water. 

liminal

adj
  • Of or pertaining to a beginning or first stage of a process. 

  • Of or pertaining to an entrance or threshold. 

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