Gambling encyclopedia

Autoplay spins a slot automatically for a chosen number of rounds; turbo spin shortens each round's animation. Neither changes the game's math — both increase spins per hour, which raises expected loss per hour proportionally, and both are restricted or banned in several regulated markets.

Bet levels and coin value build a slot's total stake: coin value sets one coin's monetary worth, bet level sets coins per payline, and total bet = coin value × bet level × lines. Modern slots increasingly replace this legacy stack with a single flat total-bet selector.

Bonus buy (feature buy) is a slot option selling direct entry to the bonus round — usually free spins — for a fixed price, typically 50–100× the bet. It skips the wait for a natural trigger; buy RTP is certified separately and often differs slightly from base-game RTP.

Cascading reels (also tumbling or avalanche reels) are a slot mechanic where winning symbols are removed after paying and new symbols fall into the gaps, re-evaluating the grid — so one spin can chain multiple wins. Cascades often feed rising multipliers, especially in free spins.

Cluster pays is a slot payout structure where wins form from groups of matching symbols touching horizontally or vertically — typically 5+ in a connected cluster — instead of lining up on paylines or adjacent reels. It is the native grammar of grid slots and usually pairs with cascading refills.

Demo mode is free play of a real casino game with virtual credits: the identical certified math model runs without real money at stake. It exists for players to learn a game's rules and rhythm before betting, and it is geo-restricted in some regulated markets such as the UK.

Free spins are a slot's in-game bonus round: a set of spins played at the triggering bet without further stake, usually started by 3+ scatters. They typically run under upgraded rules — multipliers, sticky wilds, expanded reels — and carry a large share of the game's payout potential.

A gamble feature lets a player risk a just-won amount on a simple even-or-quartered chance — classically guessing a card colour to double the win, or its suit to quadruple it. It is usually a true 50/50 with no house edge, capped in rounds and amount.

Hit frequency is the percentage of spins that produce any win — typically 20–35% for modern video slots. It measures how often a game pays, not how much: many counted 'hits' return less than the stake. Together with RTP and volatility, it completes a slot's basic statistical profile.

Hold and Win (also Hold and Spin, Lock and Respin) is a slot bonus mechanic: landing 6+ trigger coins locks them and starts respins where only new coins land and lock, each resetting the counter. The round ends when the grid fills or respins run out, paying all locked values.

Jackpot types are the distinct architectures behind slot top prizes: fixed jackpots (a set paytable amount), progressives (fed by wager contributions), local versus network pools, tiered systems (Mini/Minor/Major/Grand), must-hit-by ceilings and time-based daily drops. The type determines prize size, hit odds and who funds the prize.

Max win is the largest amount a slot can pay from a single spin or feature round, expressed as a multiple of the bet — for example 10,000×. It is a hard cap built into the certified math: once total winnings reach it, the round ends and pays the cap.

Megaways is a slot mechanic, invented and licensed by Big Time Gaming, in which the number of symbols on each reel changes every spin — so the number of ways to win varies dynamically, typically up to 117,649. It replaces fixed paylines with a per-spin recalculated ways-to-win count.

Min and max bet are the smallest and largest total stake a game accepts per spin or round. Slots build the stake from bet levels and coin values; the configured range — often $0.10 to $100 — is set by the studio and adjustable per market by the operator.

A multiplier in slots is a factor — 2x, 10x, up to unlimited progressive ladders — applied to a win before it is paid. Multipliers attach to wilds, cascades, free spins or random events, and stacking rules (adding vs multiplying together) largely determine a modern slot's win ceiling.

A must-hit-by jackpot is a progressive prize guaranteed to pay out before its meter reaches a displayed ceiling — for example "must hit by $5,000". The award point is drawn randomly below the ceiling, so the jackpot becomes statistically more attractive as the meter approaches its limit.

A mystery symbol is a placeholder that lands face-down and transforms into one randomly chosen regular symbol before wins are evaluated — every mystery on the grid reveals as the same symbol, so clusters of them can suddenly complete large simultaneous wins.

Paylines are the predefined patterns across a slot's reels along which matching symbols must land to pay a win. Classic slots use 1–25 fixed or selectable lines; a win counts only if symbols sit on an active line in the paytable-defined order, usually left to right.

A progressive jackpot is a prize pool that grows with every bet placed on connected games: a small contribution from each wager feeds the pot until one player wins it, after which it resets to a seed amount. Networked progressives pool across many casinos and can reach multi-million payouts.

Reels are the vertical columns of symbols that spin and stop to form a slot's outcome. Physical machines used 3 mechanical hoops; video slots simulate 5 or more virtual reels — ordered symbol strips the RNG stops at weighted positions. Reel count and strip composition define the game's entire math.

A respin is a follow-up spin of some or all reels while part of the previous result stays locked in place. Slots use respins as near-miss second chances, symbol-collection engines (as in Hold and Win), or purchasable extras that replay one reel at a price.

RTP (Return to Player) is the percentage of all wagered money a casino game is mathematically designed to pay back to players over the long run. A 96% RTP slot returns, on average, $96 for every $100 wagered — measured across millions of spins, not a single session.

Scatter pays is a win-evaluation system where enough matching symbols anywhere on the grid pay out, regardless of position or adjacency — no paylines, ways or clusters required. Typically eight or more matching symbols on a 6×5 grid trigger a win, usually combined with tumbling reels.

A scatter symbol is a slot symbol that pays or triggers features based on how many appear anywhere on screen, ignoring paylines and reel adjacency. Landing 3+ scatters is the standard trigger for free spins; many scatters also pay a multiple of the total bet directly.

Slot volatility (also called variance) describes how a slot distributes its payouts: low-volatility games pay small wins frequently, high-volatility games pay rarely but in larger amounts. Two slots with identical RTP can feel completely different because volatility controls the spread of results, not the average.

Sticky wilds are wild symbols that remain locked in place for multiple spins instead of disappearing after one evaluation; expanding wilds grow to cover their entire reel when they land. Both amplify the standard wild's substitution power and are staple free-spins upgrades in modern slots.

Ways to win is a slot payout structure in which matching symbols pay when they land on adjacent reels from the left, in any row position — no payline routes. The number of ways equals the product of visible symbols per reel: 3^5 = 243 ways on a 5×3 grid.

A wild symbol is a slot symbol that substitutes for other paying symbols to complete winning combinations — the joker of slot design. Wilds typically cannot replace scatters or bonus symbols, and many carry extras: multipliers, sticky behavior, expansion, or their own paytable value.

Baccarat deals two cards each to Player and Banker; totals count only the last digit (tens and faces = 0). Fixed rules may add a third card, and the hand closer to 9 wins. Bet Player (1:1), Banker (1:1 minus 5% commission) or Tie (8:1) — no decisions after betting.

Blackjack is a card game where players try to beat the dealer with a hand closer to 21 without busting. Number cards count face value, face cards ten, aces one or eleven. Played with basic strategy, its house edge falls to roughly 0.5% — the lowest of mainstream casino games.

Craps centers on the pass line: the come-out roll wins on 7 or 11, loses on 2, 3 or 12, and otherwise sets a point to repeat before a 7. Pass carries a 1.41% house edge; free odds behind it pay true odds — zero edge, the casino's best deal.

Crash games are instant multiplayer casino games where a multiplier climbs from 1.00x until it randomly 'crashes'. Players bet before the round and must cash out before the crash to win their stake times the multiplier at exit. The crash point is predetermined by provably fair math, not player actions.

Keno is a lottery-style casino game: players pick numbers (usually 1–10) from a pool of 80, the game draws 20 at random, and payouts depend on how many picks match. House edges run high — typically 5–30% — making keno one of the most expensive casino games per wager.

Live dealer casino games stream a human dealer running real table equipment — cards, wheels, dice — from a studio to players who bet through a digital interface. Outcomes come from physical randomness on camera rather than an RNG, combining online convenience with visible, verifiable play.

Mines is an instant casino game played on a grid, typically 5×5, hiding a chosen number of mines. Each safe tile revealed multiplies the payout; hitting a mine loses the bet. The player may cash out after any safe pick, and most versions are provably fair.

Plinko is an instant casino game where a ball drops through rows of pegs into multiplier slots below: central slots pay small amounts frequently, edge slots pay up to 1,000x rarely. Outcomes follow binomial probability, and players tune risk via row count and risk level. Most versions are provably fair.

Roulette odds are the win probabilities and payouts of each bet: a single number hits 1-in-37 on European wheels (2.70% house edge) and 1-in-38 on American wheels (5.26%), while even-money bets win 48.6% / 47.4% respectively. Every standard bet on a given wheel carries the same edge.

Video poker strategy is the mathematically optimal way to play five-card draw against a paytable: for every dealt hand there is one hold decision that maximizes expected value. On full-pay Jacks or Better (9/6), perfect play returns 99.54% — among the best odds any casino game offers.

Expected value (EV) is the average result of a bet if it were repeated infinitely: each possible outcome multiplied by its probability, summed. A negative EV means the bet loses money on average — true of nearly all casino wagers, where EV per unit staked equals RTP minus 100%.

House edge is the casino's built-in advantage: the average percentage of each bet the house keeps over the long run. It's the mirror of RTP — a game returning 96% to players carries a 4% house edge. Every casino game has one; it's how the business is priced.

Provably fair is a cryptographic scheme, used mainly by crypto casinos and crash games, that lets players verify game outcomes weren't manipulated. The casino commits to a hashed server seed before betting; combined with a player-controlled client seed and nonce, every result can be recomputed and audited afterwards.

A random number generator (RNG) is the certified software component that decides every outcome in a casino game. It produces a continuous stream of unpredictable numbers; the game maps each number to a reel stop, card or result, making every spin independent of the last.

RTP ranges exist because many modern slots ship in several certified RTP versions — commonly around 96%, 94% and 92% — and each casino chooses which version to run. The same game can therefore pay measurably differently between sites, making the in-game info panel, not marketing pages, the authoritative source.

Variance and volatility describe the same property of a casino game — how widely results spread around the average return. Variance is the precise statistical measure (squared deviation from expected value); volatility is the industry's player-facing label for it, usually graded low to high.

A cashback bonus returns a percentage of a player's net losses over a period — typically 5–20% weekly or monthly. Because it pays only when the player has lost, it effectively reduces the house edge; the best versions credit real funds with no wagering requirements.

A no deposit bonus is a small amount of bonus funds or free spins a casino grants for registering, before any money is deposited. It is lead-generation spend, so it carries the heaviest restrictions of any bonus type: high wagering, low max cashout, and strict verification.

Sticky and non-sticky describe whether a deposit bonus locks the player's own money. A sticky bonus pools deposit and bonus into one restricted balance; a non-sticky (parachute) bonus keeps them separate — real money plays first and can be withdrawn anytime, abandoning the bonus without penalty.

Wagering requirements (playthrough) are casino-bonus terms defining how many times the bonus — or bonus plus deposit — must be bet before winnings can be withdrawn. A $100 bonus at 35x wagering requires $3,500 in total bets — the single biggest factor in a bonus's real value.

A welcome bonus is a casino's sign-up offer for new customers — typically a percentage match on the first deposit (such as 100% up to $200), often bundled with free spins. Its real value depends on the wagering requirements and game restrictions attached, not the headline amount.

A game aggregator is a B2B intermediary that connects online casinos to many game providers through a single integration. Instead of building dozens of direct provider integrations, an operator integrates the aggregator's API once and gains access to thousands of games, paying a revenue-share margin for the convenience.

Game certification is the independent verification that a casino game's RNG, math model and published RTP behave as claimed, performed by accredited testing laboratories such as GLI, iTech Labs, BMM or eCOGRA. Regulated markets require certification per game and per jurisdiction before a title can go live.

A game provider, or game studio, is a company that designs, builds and licenses casino games — slots, table games, crash or live dealer titles — to online casino operators. Providers earn a revenue share of the gross gaming revenue their games generate, distributing through direct integrations or aggregators.

A platform provider supplies the core software an online casino runs on — the player account management (PAM) system holding registrations, wallets, payments, bonusing, compliance tooling and back office. Games and payment services plug into the platform, which acts as the operator's system of record for every player and transaction.

A remote game server (RGS) is the server infrastructure where a casino game's logic actually runs — the RNG, math model and round state. The browser client is only a renderer: every spin is a server request, and the outcome is computed and recorded on the provider's certified RGS.

A turnkey casino solution is a ready-made technology package — platform, games, payments, back office — that an operator launches under its own gambling license. Unlike a white label, the operator holds the regulatory relationship itself, buying the stack as a product while keeping control of brand, players and compliance.

A white label casino is a turnkey business arrangement where a company launches a casino brand on a provider's existing infrastructure and under the provider's gambling license. The white label partner supplies platform, games, payments and compliance; the brand owner supplies marketing and players, taking a revenue share.

AML (anti-money laundering) in gambling is the framework of laws and controls preventing casinos from being used to disguise criminal money as winnings. Licensed operators must run risk-based programs — due diligence, transaction monitoring, source-of-funds checks and suspicious-activity reporting — on pain of license loss and criminal liability.

The Curaçao gaming license is the most widely used offshore iGaming credential, historically issued through four master licenses with minimal oversight. The LOK reform (in force late 2024) replaced that system with direct licensing by the Curaçao Gaming Authority, adding real application vetting, player-protection duties and supervision.

A gambling license is official permission from a regulator to offer gambling services in or from a jurisdiction. It binds the holder to that regime's rules — player protection, funds handling, game certification, AML — and is the primary trust signal separating accountable operators from unregulated sites.

An iGaming regulator is the government body (or statutory authority) that licenses and supervises online gambling in a jurisdiction. It sets technical and conduct standards, vets operators, enforces player-protection and anti-money-laundering rules, and can fine, suspend or revoke licenses for breaches.

KYC (Know Your Customer) is the identity-verification process gambling operators must run on players: confirming who you are, your age, and — when risk triggers demand — where your money comes from. It is a license obligation rooted in anti-money-laundering law and underage-gambling prevention, not an operator whim.

The Malta Gaming Authority (MGA) is Malta's gambling regulator and the EU's leading iGaming licensing hub. Its B2C and B2B licenses cover operators and suppliers serving markets without local frameworks, combining EU-grade player protections — segregated funds, dispute resolution, certified games — with a business-friendly, tax-efficient base.

The UK Gambling Commission (UKGC) is Great Britain's gambling regulator, established under the Gambling Act 2005. It licenses all operators and key suppliers serving British consumers and is widely considered the strictest major regime — mandating GAMSTOP self-exclusion, slot design limits, stake caps for young adults and heavy AML enforcement.

Deposit limits cap how much money a player can move into a gambling account over a rolling period — daily, weekly and monthly. Decreases apply immediately; increases only after a cooling-off delay. They are the budget-enforcement layer of responsible-gambling tools, mandatory to offer in most regulated markets.

A reality check is an in-session interruption — a pop-up at set intervals showing how long you've played and, in stricter regimes, your net win/loss position — with options to continue or stop. It targets the time-distortion of absorbed play and is mandatory under licenses such as the UKGC's.

Self-exclusion is a formal, binding request to be barred from gambling for a set period or permanently. Unlike account closure, it obliges the operator — and in register-based systems like GAMSTOP, every licensed operator in the market — to block access, refuse re-entry and stop marketing for the exclusion's duration.