atop vs under

atop

prep
  • On the top of. 

  • On the top, with "of". 

under

prep
  • Below the surface of. 

  • Using or adopting (a name, identity, etc.). 

  • Subordinate to; subject to the control of; in accordance with; in compliance with. 

  • Within the category, classification or heading of. 

  • Less than. 

  • In the face of; in response to (some attacking force). 

  • In or at a lower level than; in the area covered or surmounted by. 

  • From one side of to the other, passing beneath. 

adv
  • Insufficiently. 

  • In or to a lower or subordinate position, or a position beneath or below something, physically or figuratively. 

  • In or into an unconscious state. 

  • So as to pass beneath something. 

noun
  • The amount by which an actual total is less than the expected or required amount. 

adj
  • Insufficient or lacking in a particular respect. 

  • Lower; beneath something. 

  • Under anesthesia, especially general anesthesia; sedated. 

  • In a state of subordination, submission or defeat. 

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