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 . Call upon · Act upon · Depend upon · Fall upon

Although the word upon has the same meaning as on, it is usually used in more formal contexts or in phrases such asonce upon a timeandrow upon row of seats.

There are six meanings listed in OED's entry for the adverb upon. See 'Meaning & use' for definitions, usage, and quotation evidence. This word is now obsolete.

​to ask or demand that somebody do something. She called on the government to hold a vote. I feel called upon (= feel that I ought) to warn you that…

​(formal) to start to do something or become involved in it. to enter on a new career; She entered upon a love affair which was to ruin her marriage.

rest upon · ​to depend or rely on somebody/something. All our hopes now rest on you. Extra Examples. The success or failure of the film rests largely on the ...

​to take action as a result of advice, information, etc. Acting on information from a member of the public, the police raided the club.

2 дня назад · to be something that someone will experience or have to deal with soon: Another few weeks and spring will be upon us. UPON · Be upon someone · PUT UPON · UPON in Traditional Chinese

base something on/upon something [usually passive] to use an idea, a fact, a situation, etc. as the point from which something can be developed.

​(formal) to find or meet somebody/something unexpectedly or by chance. One day he chanced upon Emma's diary and began reading it.