The word jackpot traces back to the late nineteenth century, when there were several games involving the words jack and pot. In a now-obsolete sense that emerged in 1881, the term was used in poker to describe antes beginning when no player has a card better than a jack. There were also two variants of the same poker-type game, Jacks or Better and Jack-Pots, wherein players contributed money to a central "pot" and then kept contributing more money until someone had jacks or higher. When slot machines became popular in the 1920s and 1930s, they started using the phrase jackpot for the highest payoffs, which led to the phrase hit the jackpot and the use of jackpot to mean "big prize acquired by chance". Interestingly, jackpot had a negative sense for a while: it sometimes meant "difficult situation" (from the idea that it was difficult to get out of a card game) and it was used in early 1900s criminal slang to mean "arrest".
Hello! I'm Adam Aleksic, a junior studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy trivia, politics, vexillology, geography, board games, conlanging, art history, and law.