Its origin is unknown though, I think 흥부와 놀부(folk story) is the most persuasive origin of "대박". You read this following translation of the story, you'll find out 대박 means big and round gourds filled with a lot of treasure, gold etc. <Heungbu and Nolbu> Once upon a time in a village there lives two brothers. The older brother’s name was Nolbu, and the younger brother’s name was Heungbu. Their father passed away. He passed down much wealth to the brothers, but the elder brother Nolbu alone got much of it. And after a while Nolbu kicked Heungbu and Heungbu’s family out of the house. And although Heungbu became poor, he didn’t hate his older brother. Heungbu and his family worked very hard. One spring day, a swallow built its nest under the roof of Heungbu’s home. And that swallow produced some chicks. The swallow chicks grew well. But one day a serpent got up into the swallows’ nest. The serpent tried to snatch and eat a young swallow, but it tried to escape. The young swallow fell to the ground. Its leg was broken. Heungbu helped treat the swallow’s leg. After that, the young swallow grew well. It became autumn. The weather became cold. All the swallows flew away to the south. The next spring, the swallows returned again to Heungbu’s house. One among them came holding a gourd seed in its beak. And it dropped the gourd seed in the yard of Heungbu’s house. Heungbu planted it next to his house. After a while many large gourds grew on the roof of Heungbu’s house. It became fall. Heungbu’s family cut up the gourds. In the gourds’ cores there was a lot of treasure. So Heungbu became rich. <snip> Source : http://eataradishinyourthroat.blogspot.com/

other mean... Big hit

Yes - Jackpot

Jackpot?