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New to online slots? This glossary explains every key term in plain language — from RTP and volatility to bonus features and game mechanics. Tap any term to jump straight to its definition.
Autoplay is a feature that lets you set the reels to spin automatically for a chosen number of rounds. You select your bet, pick how many spins you want, and the game plays them back-to-back without you pressing the spin button each time.
Why it matters
Autoplay is convenient for extended sessions but makes it easy to lose track of your balance. Many regulated markets now require loss limits and session timers when autoplay is active.
Bet levels and coin values determine how much you wager per spin. Coin value sets the denomination of each coin, while bet level controls how many coins are staked per payline. Together they define your total bet.
Why it matters
Adjusting your bet size affects both your potential payouts and how long your bankroll lasts. Higher bets mean bigger wins in absolute terms, but the same RTP percentage applies regardless of bet size.
Bonus Buy (also called Feature Buy) lets you pay a premium — usually 50x to 100x your bet — to skip straight into the bonus round instead of waiting for it to trigger naturally through scatter symbols.
Why it matters
It gives instant access to the most exciting part of a slot but at a steep cost. The feature is banned in some countries (like the UK) because of its high-risk nature.
After a winning combination, the winning symbols disappear and new symbols fall (or tumble) into the empty spaces from above. If the new arrangement creates another win, the process repeats. This chain reaction continues until no new wins form.
Why it matters
Cascading reels create the potential for multiple wins from a single spin. Many high-volatility slots pair cascading with increasing multipliers during bonus rounds for massive win potential.
Instead of traditional paylines, Cluster Pays slots award wins when a group of identical symbols land touching each other horizontally or vertically — usually 5 or more connected symbols. Think of it like matching tiles in a puzzle game.
Demo mode lets you play a slot game using virtual credits instead of real money. The gameplay, graphics, bonus features, and RNG behavior are identical to the real-money version — you just can't win or lose actual funds.
Why it matters
It's the best way to try a new slot before committing real money. You can explore bonus mechanics, understand volatility first-hand, and decide if a game suits your taste — all completely risk-free. That's exactly what FreeSlotsDB offers.
An Expanding Wild is a wild symbol that grows to cover an entire reel (or row) when it lands. This turns every position on that reel into a wild, dramatically increasing your chances of hitting winning combinations across multiple paylines.
Why it matters
A single expanding wild can turn a losing spin into a big win by completing combinations on several paylines at once. They're especially powerful in games with many paylines or in bonus rounds.
Free Spins are bonus rounds awarded when you land a specific number of scatter symbols (usually 3 or more). During free spins, you spin the reels without paying — but any wins are added to your balance. Free spin rounds often come with special modifiers like multipliers, extra wilds, or expanding reels.
Why it matters
Free spins are where most slots deliver their biggest payouts. The combination of zero-cost spins plus enhanced features makes the bonus round the most valuable part of any slot session.
After any base-game win, some slots offer a Gamble Feature where you can risk your winnings on a 50/50 bet — typically guessing the color or suit of a face-down card. A correct guess doubles (or quadruples) your payout; a wrong guess loses it all.
Why it matters
It adds an extra layer of risk and excitement, but the odds are never in your favor long-term. Most experienced players skip it to protect their wins.
Hit Frequency is the percentage of spins that result in any winning combination. A slot with 30% hit frequency pays out something on roughly 1 in every 3 spins, though most of those wins may be smaller than your bet.
Why it matters
Higher hit frequency means more frequent (but often smaller) wins, which keeps your balance steadier. Low hit frequency slots go through longer dry spells but tend to pay larger amounts when they do hit.
Hold and Win is a bonus mechanic where triggering symbols lock in place on the grid and you receive a set number of respins. During respins, you're trying to land more of the same symbols. Each new symbol resets the respin counter. The round ends when no new symbols land or the grid is full (a Grand Jackpot).
Why it matters
Hold and Win mechanics create suspense and the dream of filling the entire grid. Many modern jackpot slots use this system, where filling all positions awards the top-tier jackpot prize.
Max Win is the highest possible payout a slot can deliver on a single spin, expressed as a multiple of your bet. A 10,000x max win means if you bet $1, the most you can win in one spin is $10,000. Once this cap is reached, the round ends automatically.
Why it matters
The max win cap tells you the true upside potential of a slot. High-volatility games often have caps of 10,000x–50,000x or more, while low-volatility games typically cap around 500x–5,000x.
Megaways is a patented reel mechanic by Big Time Gaming where the number of symbols on each reel changes randomly every spin. With 6 reels that can show 2–7 symbols each, you get up to 117,649 different ways to win on every single spin.
Why it matters
Megaways transformed the slot industry by making every spin unpredictable and exciting. The variable reel sizes paired with cascading wins and increasing multipliers create enormous win potential.
Paylines are the predetermined patterns across the reels where matching symbols must land to form a winning combination. Classic slots might have 1–5 paylines, while modern video slots can have 10, 20, 50, or even 243+ fixed ways to win.
Why it matters
More paylines means more chances to win on each spin. Slots with 243 or 1,024 'ways to win' pay for matching symbols in any position on adjacent reels, regardless of row — eliminating traditional payline limitations.
A Progressive Jackpot is a prize pool that grows every time someone plays the game. A small portion of each bet across all connected machines or online players is added to the jackpot. It keeps growing until one lucky player triggers the win, then resets to a seed amount.
Why it matters
Progressive jackpots can reach life-changing sums — sometimes millions of dollars. However, they typically lower the base-game RTP since part of each bet funds the jackpot pool.
RTP is the percentage of all wagered money a slot is designed to pay back to players over time. An RTP of 96% means that for every $100 wagered across thousands of spins, the game returns $96 on average. The remaining 4% is the house edge.
Why it matters
RTP is the single most important number for comparing slots. Higher RTP means a smaller mathematical advantage for the casino. Look for slots with 96%+ RTP for the best long-term value. Remember: RTP is calculated over millions of spins, not your individual session.
Scatter symbols are special symbols that pay out or trigger features regardless of their position on the reels — they don't need to land on a specific payline. Landing 3 or more scatters typically triggers the bonus round (usually free spins).
Why it matters
Scatters are the gateway to bonus features, which is where the biggest wins happen. Some slots let you retrigger scatters during free spins to extend the bonus round even further.
Volatility (also called variance) describes the risk profile of a slot. Low volatility slots pay out small wins frequently. High volatility slots pay out less often, but when they do hit, the wins are significantly larger. Medium volatility is a balance between the two.
Why it matters
Choosing the right volatility level for your playstyle is crucial. Low volatility suits players who want steady entertainment and smaller swings. High volatility is for thrill-seekers willing to endure dry spells for the chance at massive payouts.
Wild symbols act as substitutes — like a joker in a card game. They can replace most other symbols to help complete winning combinations. For example, if you have two matching symbols and a wild on the same payline, the wild fills in as the third match.
Why it matters
Wilds significantly increase your chances of landing winning combinations. Many slots add special wild types — sticky wilds, walking wilds, multiplier wilds — that make them even more powerful during bonus rounds.
Now that you know the lingo, explore our library of 34,000+ free slot games — no download, no registration required.
Why it matters
Cluster Pays opens up a huge number of possible winning combinations across the entire grid. These slots often pair with cascading mechanics for chain-reaction wins.
A multiplier increases your winnings by a given factor. A 3x multiplier triples your payout. Multipliers can appear as symbols on the reels, as part of free spin mechanics (often increasing with each cascade), or as random modifiers applied to any win.
Why it matters
Multipliers are the engine behind most record-breaking slot wins. Progressive multipliers that grow during bonus rounds are what enable slots to reach their maximum win caps.