Casino glossary & wiki
Every term you'll see in slot reviews, bonus terms, sportsbook menus, and Stake Originals — defined in plain language with the math context that matters.
Math & probability
RTP (Return to Player)
The theoretical percentage of total wagered money a game returns to players over millions of spins. A 96% RTP means the house edge is 4%.
Volatility / Variance
How risky a slot's payout pattern is. Low volatility = frequent small wins. High volatility = rare but big wins. Same RTP, different ride.
House Edge
The mathematical advantage the casino has over the player. Equal to (100% − RTP). House edge is per bet, not per session.
Max Win
The maximum theoretical payout of a single spin or game session, expressed as a multiplier of the bet. Reaching max win is rare — typically 1 in millions.
Hit Frequency
The percentage of spins that result in any win, regardless of size. A 25% hit frequency means winning combinations land on roughly 1 in 4 spins.
Expected Value (EV)
The average outcome of a bet over infinite repetitions. Negative EV means long-term loss; positive EV (rare in casinos) means long-term profit.
Variance
Statistical measure of how far results spread from the expected value. High variance = wild swings. In gambling, often used interchangeably with volatility.
Technology & fairness
Game mechanics
Megaways
A slot mechanic invented by Big Time Gaming where each reel has a variable number of symbols (typically 2–7), creating up to 117,649 ways to win per spin.
Scatter symbol
A symbol that pays regardless of position on the reels and typically triggers free spins or bonus rounds when 3+ appear.
Wild symbol
A substitute symbol that replaces other symbols (except scatters) to complete winning combinations. Sticky wilds remain across spins; expanding wilds cover entire reels.
Bonus Buy / Feature Buy
A feature that lets players pay an upfront cost (typically 50×–500× their bet) to instantly trigger free spins or a bonus round.
Free Spins
Bonus rounds where the player gets a fixed number of spins without betting. Often include enhanced features like multipliers, sticky wilds, or expanded reels.
Cluster Pays
An alternative to paylines: payouts are made when 5+ identical symbols touch horizontally or vertically anywhere on the grid.
Tumble / Cascade
A mechanic where winning symbols disappear and new symbols fall into place, allowing chained wins from a single spin. Pioneered by NetEnt's Gonzo's Quest.