D defs.my
Entry 3 senses Webster, 1913

Thereupon

/thĕrˌ-əp-än'/ · There·up·on · IPA /ˌðɛɹəˈpɑn/
01 adv. Upon that or this; thereon.
  1. 1.
    Upon that or this; thereon.
  2. 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. 3.
    Immediately; at once; without delay.