Glossary of Online Casino Terms

This glossary explains the terms that come up most often in our guides and comparisons, independent of any specific operator.

RTP (Return to Player): The theoretical percentage a game pays back to players over a very large number of rounds, expressed as a percentage. An RTP of 96% means the game returns 96% of money wagered on average over the long run — the rest is the operator's edge. RTP says nothing about the outcome of any single session.
Volatility (variance): How much and how often a game's payouts fluctuate. Low volatility means more frequent, smaller wins; high volatility means rarer but potentially bigger wins, with longer losing streaks in between.
House edge: The operator's built-in mathematical advantage, usually the inverse of RTP (96% RTP → 4% house edge). It's what keeps the operator profitable long-term regardless of any single round's outcome.
RNG (Random Number Generator): The system that determines outcomes in slots and other digital games. Licensed operators must have their RNG tested and certified by independent testing labs.
Wagering requirement: The multiple you must bet through before a bonus becomes withdrawable (e.g. 35× means a €50 bonus requires €1,750 in total wagers). The lower the multiple, the more favorable the term.
Free spins: Slot rounds played without staking your own money, usually part of a welcome offer. Winnings from free spins often carry their own separate wagering requirement.
Progressive jackpot: A prize pool that grows with every wager placed on one or several linked games until a player wins it.
Live casino: Roulette, blackjack, baccarat and similar table games streamed in real time with an actual dealer, rather than generated purely digitally.
KYC (Know Your Customer): The legally required identity check (ID document, proof of address) that reputable operators must run, at the latest, before a first withdrawal.
Cashback: A partial refund of net losses over a set period, usually credited as bonus funds with their own wagering requirement.
VIP / loyalty program: A tiered system offering extra perks — dedicated support, higher limits, exclusive bonuses — to players with higher betting volume.
Self-exclusion: The option to exclude yourself, temporarily or permanently, from one operator or — through a centralized national register, where one exists — from every licensed operator in your country.