/ əˈpɒn; NAmE əˈpɑːn/ preposition
1.
( formal , especially BrE ) = on :
The decision was based upon two considerations.
HELP NOTE : Although the word upon has the same meaning as on , it is usually used in more formal contexts or in phrases such as
once upon a time
and
row upon row of seats
.
2.
... upon ... used to emphasize that there is a large number or amount of sth :
mile upon mile of dusty road
thousands upon thousands of letters
•
IDIOMS
- (almost) upon you
—more at once adverb
••
WORD ORIGIN
Middle English : from up + on , suggested by Old Norse upp á .