How to pronounce upon:
Being the target of an action.
Example: "He was set upon by the agitated dogs"
Physically above and in contact with.
Example: "Place the book upon the table."
Physically directly supported by.
Example: "She balanced upon one foot."
Being followed by another so as to form a series.
Example: "Hours upon hours, years upon years, mile upon mile of desert"
At (a prescribed point in time).
Example: "The contract was rendered void upon his death."
On.