10 Essential Online Casino Terms Every Player Should Know

The world of legal casino apps in the US has continued to grow since they first burst onto the scene in 2013. From popular casino games online to enticing online casino bonus codes, there's plenty to enjoy with regulated iGaming. There's also a deep glossary of terms that could seem like a completely different language to new users. These are the most common phrases new players will find with online casinos.

This is one of the more common casino welcome offers found at online casinos, including from the BetMGM Casino app and using the Caesars Palace Online Casino promo code.

With the deposit match bonus, once new customers make their first real-money deposit, operators will credit their accounts in the form of casino credits equal to the amount of that deposit. That bonus comes with a caveat, though, in that players will need to fulfill a playthrough requirement before it becomes eligible for withdrawal.

More on "playthrough requirement" in a minute.

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Built into every game is a set of odds set forth by game developers and online casinos, otherwise known as "house edge."

For example, online blackjack games typically hold a house edge of 0.5%, meaning that for every $100 bet in a game, the online casino expects to keep $0.50.

Users will find this kind of welcome offer using the likes of the DraftKings Casino promo code and the Fanatics Casino promo code. 

With this style of casino bonus, first-time customers will have 24 hours after opting into the promo – known as a "lossback period" – to play any online casino game they want. During this time, the online casino will keep track of net losses by that player. Once the 24-hour period ends, the operator will issue casino credits matching that net loss total.

Like the deposit match bonus (and the next term), there is a playthrough requirement to convert the bonus into withdrawable cash. Again, more on "playthrough requirement" in a second.

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Just as it sounds, new users earn casino credits just for signing up, like they can by signing up using the BetMGM Casino bonus code SPORTSLINE. Yes, BetMGM's welcome offer includes a no deposit bonus that requires a deposit, but it also comes with $25 in casino credits just for signing up in Michigan, New Jersey and Pennsylvania.

Essentially, it's just about creating an account and opting into the bonus to receive casino credits, which comes with the following requirement.

Each casino welcome offer and most bonuses overall carry a playthrough requirement, also known as "wagering requirement." With Caesars Palace Online Casino, it's a 15x playthrough requirement on the deposit match, while the FanDuel Casino promo code calls for a 1x wagering requirement.

Simplified, it's the amount an online casino requires players to wager in real money to convert bonuses into withdrawable cash. With the 15x requirement on $10 in casino credits, for example, users will need to wager $150 before they can withdraw the bonus. For FanDuel Casino's $40 in casino credits and a 1x playthrough, that total is $40 in wagers to make the bonus eligible for withdrawal.

All the top online casinos feature games with progressive jackpots. With these titles, players will see jackpots continue to increase in total the longer they go unclaimed, similar to how Powerball grand prizes work. Those jackpots are accrued across the operator's network with each play. DraftKings Casino, for example, saw one player in 2025 turned a $0.20 spin into $9.2 million playing Irish Pot Luck.

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Licensed online casinos use random number generators for their games to provide random but fair results for players. This is required by state regulators to ensure online casino games are not "rigged" in favor of operators.

When looking at slots with online casinos, players will see "RTP" rates. This total represents how much online casinos expect to pay out over a period of time. For instance, the game Wild Turkey Megaways at BetMGM Casino carries a 96.05% RTP. That means, for every $100 wagered, the casino expects to pay out around $96.

In most slots online, there are "scatter" symbols that appear when playing. These special symbols always pay out whenever they land on the reels and could also trigger free spins within the game when combined with other symbols.

Another term typically used with slots, volatility reflects how often a game pays out, ranging from low to high. Low-volatility games mean they pay out more frequently but in smaller amounts, while high-volatility titles carry bigger payouts but occur less frequently.

Grant Lucas