B1prepositionformal10K+

Upon

UK /["/əˈpɒn/"]/US /["/əˈpɑːn/"]/

Definition

used to emphasize that there is a large number or amount of something

In simple words: on or at a particular time or place

Examples

mile upon mile of dusty road
thousands upon thousands of letters
Once upon a time there was a beautiful princess.
The summer season was almost upon them again.

Usage notes

Used in more formal contexts, often in writing. Not commonly used in everyday spoken English. Avoid in casual conversations.

Grammar pattern

upon + noun

Memory hint

Think of 'upon' as 'up-on' - like reaching up on a high shelf.

Collocations

upon arrival
upon request
upon reflection
upon hearing
upon completion

Synonyms

on
at
after
about
concerning

Antonyms

after
below
underneath

Common mistakes

Confused with 'on' in casual speech.
Used inappropriately in informal settings.
Misunderstood as a preposition that can replace any instance of 'on'.