upon upon /əˈpɒn/

preposition

1. () Directly touching or resting on the surface of something.  ( upon , on )
   Directly touching or resting on the surface of something.
   
2. () Upheld or carried by.  ( on , upon )
   Upheld or carried by.
   
3. () At a specific time or immediately after a certain event.  ( on , upon )
   At a specific time or immediately after a certain event.