Slots Glossary
Plain-English glossary of slot machine and gambling terms: RTP, RNG, volatility, hit frequency, paylines, bonus buys, and more.
Last updated: May 2026 · 18+ educational content
- RTP (Return to Player)
- The long-run percentage of wagered money a slot returns to players, calculated over millions of spins.
- House edge
- The mathematical advantage the casino has on each bet. House edge = 100% − RTP.
- RNG (Random Number Generator)
- Software that produces unpredictable numbers used to determine the outcome of every spin.
- Volatility (variance)
- How swingy a slot is. Low = small frequent wins; high = rare large wins.
- Hit frequency
- The percentage of spins that return any payout, including wins smaller than the stake.
- Payline
- A specific pattern across the reels that pays when matching symbols land on it.
- Ways to win
- An alternative payline model where adjacent matching symbols pay regardless of exact position.
- Wild
- A symbol that substitutes for other symbols to complete winning combinations.
- Scatter
- A symbol that pays or triggers a bonus regardless of payline position.
- Free spins
- A bonus round of spins awarded without an additional stake, often with multipliers.
- Bonus buy
- Paying an upfront cost to instantly trigger a bonus round. Increases volatility and short-term loss risk.
- Max win
- The highest possible payout on a slot, usually expressed as a multiple of the bet (e.g. 5,000x).
- Bankroll
- The total money set aside for gambling. Should be money you can fully afford to lose.
- Stake / bet size
- The amount wagered on a single spin.
- Loss limit
- A pre-set maximum loss at which you stop playing for the session.
- Self-exclusion
- A formal request to be blocked from a gambling site or all licensed sites for a chosen period.
- Gambler's fallacy
- The false belief that past outcomes affect the probability of future independent events.