Jackpot

A jackpot is the maximum prize a slot or game can pay. It can be fixed (a preset amount) or progressive: in the latter, a small share of every bet from all players feeds a prize pool that grows until someone wins it.

Progressive jackpots have very low hit odds and contribute to the overall house edge: part of the RTP is "parked" in the jackpot and returned on average only to the winner. They are by definition extremely high-volatility.