aeriform vs gliding

aeriform

adj
  • Pertaining to air. 

  • Having a form similar to that of air. 

  • Light, unsubstantial, or unstable. 

gliding

adj
  • That moves or changes with a glide. 

  • Employing flexitime. 

noun
  • The hobby, sport, or act of flying a glider. 

  • The action or motion of something that glides. 

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