What’s the difference between odds formats (decimal, fractional, American)?

They all express the same probabilities but in different formats: Decimal (2.50) = total return per €1 Fractional (3/2) = profit relative to stake American (-150 / +200) = how much you risk or win on $100

Online Gambling Glossary 2025 | CasinoLogia Edition

What Is the Online Gambling Glossary?

Our Online Gambling Glossary is a structured index of terms used in online gambling. It covers terminology from slots, casino platforms, sports betting, bonuses, and general gambling mechanics. Each term is defined in clear language, without filler or promotional phrasing. The glossary is organized by category for easy navigation. Terms are linked across CasinoLogia’s slot reviews, bonus breakdowns, and educational pages. This allows users to move between definitions and practical applications without guesswork. The goal is accuracy. Every entry is written to clarify, not oversimplify. If a term involves math, rules, or platform-specific behavior, we include that. No speculation. No vague summaries. Just correct definitions that apply across real-world gambling products.

Use this glossary to check meanings, compare similar terms, or confirm what you’re reading elsewhere. It’s built as a reference tool, not a tutorial.

How We Define Gambling Terms

We define gambling terms with precision, not assumptions. Every entry in this glossary is based on how the term functions in practice (mathematically, legally, or operationally) across online casinos, slot mechanics, sportsbooks, or promotional structures. Definitions are written in plain language, but never dumbed down. Each term follows a consistent internal logic:

Definition: A short, clear explanation of what the term means.
Context: Where and how the term is used (slots, casino gameplay, bonuses, betting).
Technical Detail: If applicable, we include formulas, odds formats, or behavioral mechanics (e.g., how RTP affects payout distributions or how rollover works against bonus value).
Variations: If a term differs across providers, jurisdictions, or product types, that variation is listed.
Linked References: We connect terms directly to CasinoLogia’s slot reviews, bonus breakdowns, feature guides, or mechanic models.

We avoid vague generalizations like “this term is commonly used” or “players may encounter…” – that doesn’t help. Instead, each term is treated as a data point within a wider system.

For example:

Term	Game Type	Core Function	Related Concepts
RTP	Slots	Theoretical payout percentage over time	Volatility, House Edge, Hit Rate
Moneyline	Sports	Betting odds format indicating favorite/underdog	Spread, Decimal Odds, Stake

The glossary is not written for SEO filler or surface-level readers. It’s built for players who want to understand the structure behind gambling systems so they can read through bonus conditions, slot specs, or sportsbook odds without second-guessing what anything means. We also avoid recycled or ambiguous industry language. Terms like “variance,” “sticky bonus,” or “cascading reels” are broken down into their actual mechanisms, not just reworded definitions. When platforms use terms incorrectly, we note that too. The glossary is a system of reference, aligned with CasinoLogia’s core structure: logic, accuracy, and usability. Each term is a node in that system – clearly defined and cross-linked.

How to Use This Glossary

This glossary is designed as a reference tool. Here’s how to navigate it efficiently:

Step 1

Scan the Categories

Start by using the section at the top of the page. All terms are grouped by topic:

Slots
Casino Terms
Sports Betting
Bonuses
Gambling Math
Abbreviations

This keeps your search relevant and cuts out unnecessary scrolling.

Step 2

Use Ctrl+F or Your Browser Search

Looking for a specific term? Use Ctrl+F (or Command+F on Mac) to quickly search the page. This works best for one-word terms like “RTP,” “parlay,” or “wagering.”

Step 3

Click Linked Terms Across the Site

When reading a slot review, bonus guide, or feature page, you’ll notice terms are underlined or hyperlinked. Clicking on those will bring you back to the glossary entry here without the need to leave the page you're on.

Step 4

Read the Full Definition

Each entry includes:

Definition (what it means)
Application (where and how it’s used)
Related Terms (linked for cross-reference)

If you’re new to a concept, scan the related terms to get the full picture.

Step 5

Follow Cross-Links to Deeper Content

Many glossary terms link directly to our long-form articles, slot mechanic breakdowns, or visual explainers. Use these to go beyond the definition and see the term in real-world use.

Slot Terms

Slot games are built on technical systems like math models, trigger mechanics, and payout logic. Understanding the terms used in slot descriptions isn’t optional if you want to know what you’re playing. Let’s break down the most frequently used terminology across modern video slots, classic machines, and advanced feature-driven releases.

RTP (Return to Player)

RTP stands for Return to Player. It represents the theoretical percentage of wagered money a slot is designed to pay back over time. For example, a slot with 96% RTP will, on average, return €96 for every €100 wagered over a statistically significant number of spins.

RTP does not guarantee short-term results. It's calculated over millions of simulated rounds. If a game advertises 96.50% RTP, that’s a built-in parameter, not a live payout tracker. Many providers offer variable RTP ranges, and some operators may run the same game at different RTP settings. Always check the slot info panel or provider site for the exact value.

Related terms: House Edge, Volatility, Hit Rate

Volatility (Variance)

Volatility (also called variance) defines the risk profile of a slot. It determines how often a game pays out and how large those payouts typically are:

Low volatility = frequent, small wins
Medium volatility = balanced payouts and frequency
High volatility = rare wins, high payout potential

High-volatility slots are often linked to bonus buys, max win caps, or jackpot triggers. Low-volatility games, in contrast, are more consistent but less rewarding in peak wins. Volatility isn't displayed as a number but can often be inferred from the paytable and bonus structure. Some providers assign it a label or visual scale.

Related terms: RTP, Hit Frequency, Bonus Buy

Paylines

A payline is the pattern across reels that determines how symbols must align for a payout. Classic slots may have just 1–5 paylines; modern video slots often feature 10, 20, 40, or more. Some use 243 ways to win or Megaways, which aren’t traditional paylines but variable reel combinations.

Wins are paid when matching symbols land on an active payline, usually from left to right. The number of paylines affects both volatility and bet size. Some games allow you to choose how many paylines are active; others have fixed lines.

Related terms: Megaways, Cluster Pays, Ways to Win

Casino Terms

Casino platforms run on rules, limitations, and system logic. Understanding how casinos define things like house edge, limits, and account rules helps players navigate account restrictions, payout structures, and bonus enforcement.

House Edge

House edge is the built-in statistical advantage a casino has over the player, expressed as a percentage. It’s the inverse of RTP. For example, a game with 96% RTP has a 4% house edge.

This figure represents the long-term expected profit the casino will keep from each wager. It doesn’t mean you’ll lose 4% every session – it’s a projection over millions of rounds. Different games have different house edges. Slots typically have 3-6%. Table games like blackjack or baccarat can drop below 1% with optimal strategy. House edge is how casinos ensure profitability over time. It’s non-negotiable and baked into the game’s math model.

Related terms: RTP, Expected Value, Variance

Wagering Requirements

Wagering requirements (WR) are conditions that apply to bonuses. They indicate how many times you must wager the bonus (or bonus + deposit) before you can withdraw any winnings.

Example: A €100 bonus with a 40x WR means you must bet €4,000 before the funds become withdrawable.

WRs can apply to:

Bonus only
Bonus + deposit
Free spin winnings
Cashback payouts

Always check if there are max bet rules, restricted games, or time limits tied to the requirement. Casinos use WRs to control bonus abuse and protect their margins.

Related terms: Sticky Bonus, Max Bet, Bonus Abuse

KYC (Know Your Customer)

KYC stands for Know Your Customer. It’s a mandatory verification process required by licensed casinos to confirm your identity, age, and address. It usually involves uploading:

ID card or passport
Utility bill or bank statement
Payment method proof (e.g., screenshot of e-wallet or credit card)

You’ll be asked to complete KYC before your first withdrawal or during large transactions. Delaying KYC can result in frozen accounts or blocked withdrawals.

This is not optional. It's enforced by regulators as part of anti-money laundering (AML) and responsible gambling laws.

Related terms: AML, Withdrawal Policy, Account Verification

Sports Betting Terms

Sports betting is a numbers game backed by terminology. Understanding odds, stake types, bet structures, and outcome conditions is essential, especially when comparing markets or calculating returns. This section breaks down the most common terms you’ll see on sportsbooks, bet slips, and in-play markets.

📊 Most Popular Sports Betting Terms

Term	Definition	Example
Moneyline	A straight bet on which team or player will win.	Betting on Brazil to win a match at -150 (you stake €150 to win €100).
Spread	A handicap applied to balance betting odds between two teams.	Lakers -6.5 means they must win by 7+ points for your bet to win.
Over/Under	Betting that the total combined score will be over or under a set line.	Over 2.5 goals means 3+ goals needed for a win.
Parlay	A bet combining multiple selections that all must win for a payout.	A 3-leg parlay: Real Madrid, Bayern, and PSG all must win.
Stake	The amount of money wagered on a bet.	A €50 stake on odds of 2.00 returns €100 total (€50 profit).
Decimal Odds	Shows total return per €1 bet, including your stake. Common in Europe.	Odds of 3.50 return €350 from a €100 bet.
American Odds	Based on $100 win/loss. Negative = favorite, positive = underdog.	-120 = bet €120 to win €100; +200 = bet €100 to win €200.
Handicap	A points/goals advantage given to the underdog.	+1.5 handicap means your team can lose by 1 and you still win the bet.
In-Play Betting	Live bets placed after a match has started.	Betting on the next team to score during the second half.
Void Bet	A bet that is canceled-stake refunded. Usually happens due to match issues.	A tennis match ends due to injury; your bet is voided, and stake returned.

Bonus & Promotion Terms

Casino bonuses come with restrictions, rules, and technical conditions that aren't always obvious. It doesn’t matter if it’s wagering requirements, payout caps, or game eligibility, understanding bonus terminology is critical before opting in. This section defines the most common bonus-related terms used across promotions, free spins, cashback offers, and no-deposit deals.

Sticky Bonus

A sticky bonus is a non-withdrawable bonus amount. You can use it to play and win, but the bonus itself is removed when you request a withdrawal.

Example: You receive a €100 sticky bonus and win €400. When you request a withdrawal, the casino deducts the €100 bonus so you withdraw €300.

Sticky bonuses are used to boost bankrolls while protecting the casino’s exposure. They're often paired with high wagering requirements and max bet restrictions.

Related terms: Wagering Requirements, Bonus Balance, Max Bet

No Deposit Bonus

A no deposit bonus is a small bonus or free spins package given without requiring any deposit. It’s commonly used as a sign-up offer to attract new players.

Winnings from no deposit bonuses are usually capped (e.g., €20 max cashout) and tied to strict wagering requirements. In most cases, players must complete KYC verification before any withdrawal is allowed.

Example: You get 20 free spins with no deposit and win €15. After meeting a 30x wagering requirement, you may be allowed to cash out up to €20.

Related terms: Free Spins, Cashout Cap, KYC

Max Bet Rule

The max bet rule restricts the size of individual bets while a bonus is active. If you exceed the limit (even once) the bonus and associated winnings can be forfeited.

Example: The max bet is €5 while using a bonus. You place a €6 spin. The casino reserves the right to void all bonus funds and winnings.

This rule is common across nearly all welcome bonuses, especially in high-volatility games. It exists to prevent bonus abuse by betting high and cashing out quickly.

Related terms: Wagering Abuse, Terms & Conditions, Bonus Forfeit

More Bonus Terms

Term	Definition	Example
Welcome Bonus	A bonus offered to new users after their first deposit.	100% match up to €200 + 100 free spins on Book of Dead.
Free Spins	Slot spins granted by the casino, often tied to specific games.	50 free spins on Starburst, valued at €0.10 each.
Reload Bonus	A deposit bonus offered to existing players; usually lower than welcome bonuses.	50% bonus up to €100 on your next deposit.
Cashback	A percentage of your net losses returned as real or bonus funds.	10% cashback on losses every Monday, paid as bonus funds.
Wagering Multiplier	Indicates how many times you must wager the bonus before withdrawing.	40x wagering on a €100 bonus = €4,000 in bets required.
Eligible Games	Games that contribute to wagering. Not all games are included.	Free spins usable only on Sweet Bonanza; table games excluded.
Bonus Code	A code you must enter during deposit to claim the bonus.	Use code LOGIA100 to claim the welcome offer.
Cashout Cap	The maximum amount you can withdraw from bonus-related winnings.	€100 max cashout from a no-deposit bonus.
Wagering Contribution	The % a game contributes to wagering requirements.	Slots = 100%, live roulette = 10%, blackjack = 5%.
Opt-In Requirement	Some bonuses require manual opt-in, not automatic application.	Click “Join Now” to activate the weekend reload bonus.

Gambling Math & Mechanics

Understanding gambling without math is like trying to navigate a casino blindfolded. Behind every slot spin, sportsbook line, or bonus offer lies a structured system of probabilities, distributions, and statistical trade-offs.

📐 The Core Equation: How Outcomes Are Modeled

Most gambling systems follow this logic:

Player EV = (Win Probability × Payout) – (Loss Probability × Bet)

This formula helps you evaluate any wager – from slot spins to accumulator bets. The closer your EV (Expected Value) is to zero, the lower the house edge. The further into negative territory it goes, the more statistically unsustainable the bet becomes.

🎲 Slot Mechanics: Volatility vs. RTP vs. Hit Frequency

Term	Definition	Impact
RTP	Long-term average payout percentage.	Higher RTP = mathematically better for the player.
Volatility	Distribution of wins (frequency vs. size).	High volatility = less frequent but bigger wins.
Hit Frequency	Probability of landing any win on a spin.	1 in 5 spins = 20% hit frequency.

➡ These three variables don’t exist in isolation.
A game with 96.5% RTP, high volatility, and 18% hit frequency might yield 1-2 large wins every 100 spins, while a 94% RTP slot with 32% hit frequency will pay more often, but in smaller amounts.

🧮 Wagering Requirement Calculations

To evaluate the real value of a bonus:

Effective Value = (Bonus Amount) ÷ (Wagering Requirement)

But this ignores volatility and cashout caps. To refine that:

Adjusted EV = [(Bonus Amount × RTP) – Bet Risk – Max Cashout Impact] ÷ Wagering Amount

➡ Example:
€100 bonus × 96% RTP = €96 potential return
€4,000 required wagering at medium volatility
If the max cashout is €200, your true EV may be far below the theoretical return.

⚖️ Risk Management: Bankroll Theory in Practice

Concept	Meaning	Why It Matters
Unit Betting	Fixed percentage of bankroll per bet (e.g., 1-2%).	Prevents rapid losses and allows for long-term play.
Risk of Ruin	Probability of losing entire bankroll.	Increases with high variance, large bets, or small bankroll.
Bet Sizing	Adjusting stake based on game volatility and bankroll.	Higher variance = smaller bets to absorb swings.

🔄 Common Player Mistakes – And the Math Behind Them

Mistake	Why It’s Wrong
Chasing losses	Past results don’t change future probabilities (Gambler’s Fallacy).
Thinking higher RTP = faster wins	RTP is long-term. Short sessions are governed by variance and random distribution.
Believing bonuses = free money	With high WR and volatility, most bonuses carry negative EV unless conditions are ideal.

General Gambling Vocabulary

These are foundational terms used across all areas of gambling like slots, casinos, betting, bonuses, and user accounts.

Term	Definition
Bankroll	The total amount of money a player sets aside for gambling.
Stake	The amount of money wagered on a single bet or spin.
Bet	A wager placed on the outcome of a game or event.
Winnings	The payout received when a bet or spin results in a win.
Payout	The amount awarded to the player based on a winning outcome.
Odds	The numerical expression of probability and potential payout.
RTP	Return to Player; theoretical percentage paid back over time.
House Edge	The built-in casino advantage over the player, inverse of RTP.
Variance	Statistical measure of risk or payout distribution.
Volatility	Practical indicator of win frequency vs. payout size.
Hit Rate	The percentage of spins or bets that result in any win.
Session	A continuous period of play using a set bankroll.
Bonus	Promotional credit or spins granted by a casino or platform.
Free Spins	Spins provided at no cost, often tied to specific slot games.
Cashback	Partial return of losses, usually as bonus or real funds.
Max Bet	The maximum allowed bet while playing with an active bonus.
Wagering Requirement	The multiplier determining how much must be wagered before bonus withdrawal.
Account Balance	The total funds available in a user’s casino account.
Bonus Balance	The portion of funds designated as bonus, separate from real money.
KYC	Know Your Customer; mandatory ID verification process.
AML	Anti-Money Laundering; legal framework for financial activity monitoring.
Cashout	Withdrawal of funds from the casino account to a personal account.
Deposit	Transfer of funds into a casino or sportsbook account.
Withdrawal	The process of transferring funds out of the casino to the player’s account.
Cooldown	A self-imposed or platform-mandated pause from gambling activity.
Self-Exclusion	A formal request to block access to gambling platforms for a set period.
Regulator	A licensed authority that oversees gambling activity and enforces rules.
Operator	The company running the casino or sportsbook platform.
Provider	The game developer or studio behind the slot, table, or sportsbook software.
Terms & Conditions	The legal framework defining user behavior, limits, and rights.

Abbreviations & Acronyms

Online gambling platforms are filled with shorthand technical acronyms, regulatory terms, and feature labels that often go unexplained. This section decodes the most widely used abbreviations across slots, bonuses, sports betting, payments, and compliance. Each entry includes the full term and its direct application within gambling systems.

Common Gambling Abbreviations & What They Mean

Abbreviation	Full Term	Meaning / Use in Gambling
RTP	Return to Player	Theoretical payout percentage of a game.
EV	Expected Value	Average return calculation used in bets and bonus evaluations.
WR	Wagering Requirement	Multiplier determining how much you must wager before bonus funds become withdrawable.
KYC	Know Your Customer	Identity verification process for player accounts.
AML	Anti-Money Laundering	Regulatory framework to prevent illicit fund movement.
VIP	Very Important Player	High-value user tier with exclusive benefits.
GGR	Gross Gaming Revenue	Total player losses before costs, used by operators and regulators.
UI	User Interface	The design and layout of the casino or app platform.
RNG	Random Number Generator	The algorithm ensuring game outcomes are random and fair.
FS	Free Spins	Promotional spins on slot games.
NPB	No Purchase Bonus	Bonus granted without a deposit requirement.
BR	Bankroll	Total funds set aside by a player for gambling.
FTD	First-Time Deposit	A user’s first deposit – often linked to a welcome bonus.
UI/UX	User Interface / User Experience	Design quality and usability of casino software or app.
SDK	Software Development Kit	Used by providers and affiliates to integrate games or tools.
T&C	Terms and Conditions	Legal rules governing gameplay, bonuses, and account use.
IGT	International Game Technology	A major game provider, often abbreviated in slot listings.
HTML5	HyperText Markup Language v5	Standard framework for modern browser-based games.
NGR	Net Gaming Revenue	GGR minus bonuses, taxes, and operational costs.
CPA	Cost Per Acquisition	Marketing model based on paying per referred player.

Online Gambling Glossary – FAQs

RTP (Return to Player) is the percentage a game is expected to return to players over time. House Edge is the inverse – it's the casino's statistical advantage. For example, a slot with 96% RTP has a 4% house edge.

Volatility (or variance) measures risk and payout distribution. High volatility slots offer less frequent but larger wins. Low volatility slots pay smaller amounts more often.

Wagering Requirements tell you how many times you must bet the bonus (or bonus + deposit) before withdrawing. A 40x WR on a €100 bonus means you must wager €4,000 before cashing out.

A sticky bonus cannot be withdrawn. You can use it to play and win, but when you withdraw, the bonus amount is removed from your balance.

No. Hit frequency is how often a slot pays out. RTP measures how much it pays over time. A game can have high hit frequency but low RTP if it pays small amounts frequently.

KYC (Know Your Customer) is a mandatory identity check. Casinos use it to comply with anti-money laundering laws and prevent underage gambling.

The max bet rule limits how much you can bet while using bonus funds. Exceeding it—even once—can lead to forfeiting the entire bonus and winnings.

Your bankroll is the total amount of money you've set aside specifically for gambling. Managing it properly is essential for avoiding unsustainable losses.

Expected Value helps estimate the mathematical outcome of a bet. A negative EV means the bet will lose money in the long run. It’s used for analyzing bonuses, sports bets, and slot outcomes.

They all express the same probabilities but in different formats:

Decimal (2.50) = total return per €1
Fractional (3/2) = profit relative to stake
American (-150 / +200) = how much you risk or win on $100

Online Gambling Glossary CasinoLogia Edition

Online Gambling Terminology by Category