Definitions

1. conjunction

used to indicate the place where something is happening or is to be done

“She stood whereupon the old oak tree stood for centuries.”

2. noun

the place where something is happening or is to be done

“The ceremony took place whereupon the king would be crowned.”

3. preposition

used to indicate the place where something is happening or is to be done

“He waited whereupon the bus would stop.”