Source : Webster's Revised Unabridged Dictionary (1913)

Thereupon \There`up*on"\, adv.
   1. Upon that or this; thereon. ``They shall feed thereupon.''
      --Zeph. ii. 7.

   2. On account, or in consequence, of that; therefore.

            [He] hopes to find you forward, . . . And thereupon
            he sends you this good news.          --Shak.

   3. Immediately; at once; without delay.

Source : WordNet®

thereupon
     adv : immediately after that; "thereupon the entire class
           applauded"; "with that, she left the room"; "I
           therewith withdraw my complaints" [syn: {therewith}, {with
           that}]