Definition of jackpot. 1a : the top prize in a game or contest (such as a lottery) that is typically a large fund of money formed by the accumulation of unwon prizes. b(1) : a hand or game of draw poker in which a pair of jacks or better is required to open.
jackknife-fish, jackleg, jacklight, jacklighter, jacklin, jackpot, jackrabbit, jacks, jackscrew, jackshaft, jacksie. an outstanding reward or success. hit the jackpot, Informal. to achieve a sensational success; have sudden luck: The firm has hit the jackpot with its new line of computers.
When that happens, the arachnids are commonly seen as winning the vertebrate jackpot. SOFIA can, and over the course of two years of observations, the NASA team hit the molecular jackpot, finding the precise fingerprint of water scattered across Clavius.
A jackpot is a big winning -- often the largest a competition or event has to offer. Let's say John Doe goes to Las Vegas to get away from his wife for a few days. He puts a few dollars in a slot machine and pulls the handle. Three red cherries pop up, lights start flashing, and music starts playing.