[1] : The Collaborative International Dictionary of English v.0.48

upon \upon"\, prep.as. uppan, uppon; upp up + on, an, on. see
   up, and on.
   on; -- used in all the senses of that word, with which it is
   interchangeable. "upon an hill of flowers." --chaucer.
   1913 webster

         our host upon his stirrups stood anon.   --chaucer.
   1913 webster

         thou shalt take of the blood that is upon the altar.
                                                  --ex. xxix.
                                                  21.
   1913 webster

         the philistines be upon thee, samson.    --judg. xvi.
                                                  9.
   1913 webster

         as i did stand my watch upon the hill.   --shak.
   1913 webster

         he made a great difference between people that did
         rebel upon wantonness, and them that did rebel upon
         want.                                    --bacon.
   1913 webster

         this advantage we lost upon the invention of firearms.
                                                  --addison.
   1913 webster

         upon the whole, it will be necessary to avoid that
         perpetual repetition of the same epithets which we find
         in homer.                                --pope.
   1913 webster

         he had abandoned the frontiers, retiring upon glasgow.
                                                  --sir. w.
                                                  scott.
   1913 webster

         philip swore upon the evangelists to abstain from
         aggression in my absence.                --landor.
   1913 webster

   note: upon conveys a more distinct notion that on carries
         with it of something that literally or metaphorically
         bears or supports. it is less employed than it used to
         be, on having for the most part taken its place. some
         expressions formed with it belong only to old style;
         as, upon pity they were taken away; that is, in
         consequence of pity: upon the rate of thirty thousand;
         that is, amounting to the rate: to die upon the hand;
         that is, by means of the hand: he had a garment upon;
         that is, upon himself: the time is coming fast upon;
         that is, upon the present time. by the omission of its
         object, upon acquires an adverbial sense, as in the
         last two examples.
         1913 webster

   to assure upon law, to promise; to undertake.

   to come upon. see under come.

   to take upon, to assume.
      1913 webster
see also:
up on to assure upon to come upon come to take upon 

Upon >> U Words
Upon, definition of term: Upon
upon_pag1.html

Assure >> A Words
Assure, definition of term: Assure
assure_pag1.html

Look Upon >> L Words
Look Upon, definition of term: Look Upon
look+upon_pag1.html

Bear Upon >> B Words
Bear Upon, definition of term: Bear Upon
bear+upon_pag1.html

Agreed Upon >> A Words
Agreed Upon, definition of term: Agreed Upon
agreed+upon_pag1.html

Call Upon >> C Words
Call Upon, definition of term: Call Upon
call+upon_pag1.html