upon

Etymology

From Middle English upon, uppon, uppen, from Old English upon, uppon, uppan (“on, upon, up to, against, after, in addition to”), equivalent to up (“adverb”) + on (“preposition”). Cognate with Icelandic upp á, upp á (“up on, upon”), Swedish på (“up on, upon”), Danish på (“up on, upon”), Norwegian på (“up on, upon”).

prep

1. Physically above and in contact with.
   Place the book upon the table.
   Yesterday, upon the stair / I met a man who wasn’t there / He wasn’t there again today / I wish, I wish he’d go away … 1899, Hughes Mearns, Antigonish
2. Physically directly supported by.
   The crew set sail upon the sea.
   She balanced upon one foot.
3. Being followed by another so as to form a series.
   hours upon hours, years upon years, mile upon mile of desert
4. At (a prescribed point in time).
   The contract was rendered void upon his death.
5. On.