Definitions:

1. A large cash prize that accumulates until it is won, typically the result of successive rounds of play in which the prize is not claimed, allowing it to grow larger. NOUN
   • She hit the jackpot on the slop machine and won a million dollars.
2. Term used metaphorically to describe a situation where someone experiences a significant success or gain, often unexpectedly. NOUN
   • Landing that big contract was a real jackpot for the small business.

Synonyms:

• gain
• reward
• windfall
• Winnings