adv. 1. Upon that or this; thereon. “They shall feed thereupon.” Zeph. ii. 7. [ 1913 Webster ]
2. On account, or in consequence, of that; therefore. [ 1913 Webster ]
[ He ] hopes to find you forward, . . . And thereupon he sends you this good news. Shak. [ 1913 Webster ]
3. Immediately; at once; without delay. [ 1913 Webster ]