Online casinos come with their own language. RTP, volatility, wagering, scatters, KYC: it can feel like a lot when you're starting out. This casino terms glossary explains the terms you'll see most often in plain English, with links to our in-depth guides where you want to learn more.
Bookmark this page and come back whenever you hit a term you're not sure about.
A
Action: The total amount you've bet. 'Lots of action' means lots of betting.
All-ways (or 'ways to win'): A slot format where matching symbols on adjacent reels count as wins without fixed paylines, such as 243 ways.
American roulette: Roulette with two zero pockets (0 and 00) and a 5.26% house edge. See American vs European roulette.
Autoplay: A slot setting that spins automatically for a set number of rounds.
B
Bankroll: The money you've set aside for gambling. Read our bankroll management tips.
Basic strategy: The mathematically best way to play each blackjack hand. See how to play blackjack online.
Bonus round: A special feature inside a slot, such as free spins or a pick-and-win game.
Bust: In blackjack, going over 21. Also used to mean losing your whole bankroll.
C
Cashback: A percentage of your losses returned to you, as cash or bonus funds.
Cashier: The part of the casino where you deposit and withdraw.
Cluster pays: A slot format where wins come from groups of matching symbols touching each other, rather than lines.
D
Demo mode: Playing a game with virtual credits instead of real money.
Double down: In blackjack, doubling your bet in exchange for exactly one more card.
E
European roulette: Roulette with a single zero and a 2.70% house edge.
Expanding wild: A wild symbol that grows to cover an entire reel.
F
Fixed jackpot: A top prize that stays the same size, unlike a progressive jackpot.
Free spins: Spins you don't pay for, awarded by a slot feature or as a casino bonus.
H
Hit frequency: How often a slot produces any win, shown as a percentage of spins.
Hold & Spin: A slot feature where special symbols lock in place while you get respins to land more. See our Crimson Castle review for an example.
House edge: The casino's built-in mathematical advantage on a game, shown as a percentage. See RTP vs house edge.
I
Insurance: A blackjack side bet that the dealer has blackjack when showing an ace. Basic strategy says not to take it.
K
Keno: A lottery-style game where you pick numbers and 20 are drawn from 80. See how to play keno.
KYC (Know Your Customer): Identity checks a casino carries out, usually before your first withdrawal. See online casino withdrawal times.
L
Leaderboard: A ranking of players in a promotion, usually by points earned through play.
Lightning Network: A fast payment layer on top of Bitcoin, used for Cash App deposits. See Cash App casino guide.
Loyalty program: A scheme that rewards regular play with points and perks. See casino VIP programs.
M
Martingale: A betting system where you double your bet after every loss. See do betting systems work?.
Max bet: The largest bet allowed on a game, or under a bonus's terms.
Max cashout: The most you can withdraw from bonus winnings.
Multiplier: A feature that multiplies a win, such as 2x or 5x.
N
No-deposit bonus: A bonus given without requiring a deposit. See our no deposit bonus guide.
P
Paytable: The screen that shows a game's symbols, payouts and rules. Always worth reading before you play.
Payline: A line across the reels on which matching symbols create a win.
Progressive jackpot: A jackpot that grows with every qualifying bet until someone wins it. See progressive jackpots explained.
Push: A tie, where your bet is returned.
R
Reload bonus: A bonus on a deposit after your first.
RNG (random number generator): The software that makes every spin or deal random and independent.
RTP (return to player): The percentage of all money wagered that a game is designed to pay back over a very long period.
S
Scatter: A slot symbol that pays or triggers a feature wherever it lands, not just on a payline.
Session: One continuous period of play.
Split: In blackjack, splitting a pair into two separate hands.
Stablecoin: A cryptocurrency designed to keep a steady value, usually one US dollar, such as USDT or USDC. See Bitcoin casino guide.
Sticky bonus: A bonus that can be played with but not withdrawn.
T
Table limit: The minimum and maximum bets allowed at a table game.
V
Volatility (variance): How a game pays out: frequent small wins (low) or rare big wins (high). See slot volatility explained.
VIP program: An exclusive rewards tier for the most active players. Explore the Diamond Reels VIP Room.
W
Wagering requirement (playthrough): The amount you need to bet before you can withdraw bonus winnings. See wagering requirements explained.
Wild: A symbol that substitutes for other symbols to complete a win.
FAQ
What does RTP mean in a casino?
RTP stands for return to player. It's the percentage of all money wagered that a game is designed to pay back over a very long period. It doesn't predict any single session.
What is the difference between RTP and volatility?
RTP tells you how much a game pays back over the long run. Volatility tells you how it pays: frequent small wins or rare big ones.
What does wagering requirement mean?
It's the total you need to bet before you can withdraw winnings from a bonus, written as a multiplier such as 30x.
What is KYC at an online casino?
KYC (Know Your Customer) means identity checks. Casinos verify your ID and address, usually before your first withdrawal.
Keep Learning
Now that you've worked through our casino terms glossary and know the language, you're ready to explore. Start with our beginner's guide to online casinos, then dive into whichever game or topic interests you most.
Put your knowledge to play at Diamond Reels
Play responsibly. Diamond Reels is for players aged 21 and over. Gambling should be entertainment, not a way to make money. Set limits before you play, and if gambling stops being fun, call or text 1-800-GAMBLER (1-800-426-2537) for free, confidential support, or visit our Responsible Gaming page.
