On and upon
What’s the difference between on and upon? The short answer is; a difference in formality. ‘On’ is generally considered to be more common, and is preferred for everyday use. ‘Upon’ on the other hand, is far more formal, and should not be used all the time, instead of ‘on’. The two words, ‘on’ and ‘upon’ are mostly interchangeable, but not always.
Both words function as prepositions and adverbs (also, ‘on’ can be an adjective). Anytime, ‘on’ is being used, ‘upon’ could take its place, if the speaker wanted to do so. It’s generally best to use ‘on’ most of the time and use ‘upon’ more sparingly.
(1) Following; examples with ‘on’.
- I went on a school trip to Salamanca, Spain.
- Samuel put the books back on the shelf where they belong.
- I’ll be waiting for you on the third floor.
- On arrival, beware of the dogs.
- You can only enter on my authorisation.
(2) Following; the same examples, but with ‘upon’.
- I went upon a school trip to Salamanca, Spain.
- Samuel put the books back upon the shelf where they belong.
- I’ll be waiting for you upon the third floor.
- Upon arrival, beware of the dogs.
- You can only enter upon my authorisation.