ethereal vs preternatural

ethereal

adj
  • Consisting of ether; hence, exceedingly light or airy; tenuous; spiritlike; characterized by extreme delicacy, as form, manner, thought, etc. 

  • Pertaining to the (real or hypothetical) upper, purer air, or to the higher regions beyond the earth or beyond the atmosphere. 

  • To do with diethyl ether. 

  • Pertaining to the immaterial realm, as symbolically represented by, or (in earlier epochs) conflated with, such atmospheric and extra-atmospheric concepts. 

preternatural

adj
  • Beyond or not conforming to what is natural or according to the regular course of things; strange. 

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