Studios invent names for their mechanics at a steady rate, and the same idea can appear under three different labels in three different games. This glossary groups the terms by what they do rather than listing them alphabetically, so related ideas sit together. Each entry gives a plain definition and, where possible, a game in the SlotsRanker catalogue that uses it, with the detail taken from that game's published rules. If a term is not here, the game's own help screen is the authority: UK standards require the rules to be accurate and understandable before play.

Symbols that stand in for others

Wild. A symbol that substitutes for other paying symbols to complete a win. Most wilds do not replace scatters. In Cleopatra, the Cleopatra wild also doubles any win it helps form.

Expanding wild. A wild that grows to fill its whole reel once it lands. The Horus symbol in Eye of Horus expands to cover reels 2, 3 and 4.

Multiplier wild. A wild that carries a value applied to wins it takes part in. In The Dog House Megaways 1000, wilds carry values from 1x to 1,000x on reels 2 to 5.

Sticky wild. A wild that stays in place for several spins, usually for the rest of a bonus round. The Dog House Megaways 1000 offers a Sticky Wilds free spins mode.

Random wild. A wild added to the grid by the game rather than landing naturally. The same game's Random Wilds mode adds up to six per spin and clears them afterwards.

Stacked wild. A wild that appears as a column of several symbols on one reel. White Orchid uses stacking wilds on reels 2 to 5.

Collector wild. A wild that gathers values shown on other symbols. The fisherman in Big Bass Splash collects fish values during free spins, and Fishin Frenzy uses the same idea with its fisherman wild in free games.

Symbols that start something

Scatter. A symbol that pays or triggers a feature wherever it lands, without needing a line. In Cleopatra, the Sphinx scatter pays on the total stake and three or more start free spins.

Reel-restricted scatter. A scatter that can only land on certain reels. White Orchid's flower scatter lands on reel 3 alone.

Super scatter. A rarer scatter that leads to a stronger bonus. In The Dog House Megaways 1000, Super Scatters unlock two Super Bonus levels.

Bonus symbol. A general label for any symbol that starts a feature. Golden Winner uses three, four or five Bonus scatters for 10, 15 or 20 free spins.

Mechanics that change the grid

Payline. A fixed path across the reels on which matching symbols must line up. Big Bass Splash has 10 fixed lines.

Adjacent pays (both ways). A line system that pays from left to right and from right to left. Lucky Pharoah uses 10 lines that pay both ways.

Ways to win. Wins form from matching symbols on adjacent reels in any row. Huff N' Even More Puff Grand uses 243 ways.

Megaways. Big Time Gaming's mechanic, launched in 2016, in which reel heights change every spin for up to 117,649 ways. See our Megaways guide.

Scatter pays or pay anywhere. Matching symbols count anywhere on the grid, usually eight or more. Sweet Bonanza 2500 uses this on a 6x5 grid.

Cluster pays. Groups of touching matching symbols form wins. Sugar Rush 1000 pays for clusters of five or more on a 7x7 grid.

Tumble or cascade. Winning symbols disappear and new ones fall into the gaps, allowing several wins from one spin.

CollectR. ELK Studios' system in Pirots 5, where collector birds gather matching gems across a 6x6 grid that can expand to 8x8.

Grid expansion. The playing area grows during a spin or feature, as in Pirots 5's expansion to 8x8.

Nudge. A reel or symbol moves by one or more positions after landing. Fortune Garuda 500 uses Nudge and Nudge Wild on its special reel.

Multipliers and how they combine

Multiplier. A value applied to a win. The catch is in how several multipliers are combined, which varies by game.

Added multipliers. Values are summed. A 2x and a 3x become 5x.

Multiplied multipliers. Values are multiplied together. In The Dog House Megaways 1000, a 5x and a 10x wild on the same way give 50x, not 15x.

Multiplier orb or bomb. A symbol carrying a value that is collected and applied at the end of a tumble sequence. Pragmatic Play's page for Sweet Bonanza 2500 describes candy bomb values of up to 2,500x in free spins, added together and applied to the total win.

Spot or position multiplier. A multiplier attached to a grid cell rather than a symbol. In Sugar Rush 1000, repeated wins on a cell double its multiplier up to x1,024. In Duck Hunters, each cell keeps a multiplier that doubles on repeated hits, up to x8192.

Special multiplier reel. A separate reel whose value multiplies a line win. Fortune Garuda 500's reel carries values from 1x to 500x.

Progressive multiplier. A multiplier that increases step by step during a feature. Golden Winner moves along a 12-step trail that raises its multiplier to 10x.

Bonus rounds and their variants

Free spins. Spins played without taking a new stake, usually started by scatters. Wins are normally valued at the stake of the spin that started the round.

Retrigger. Landing more scatters during free spins to add spins. Cleopatra's round can retrigger up to 180 spins in total.

Retrigger ladder. Extra rewards for progress inside the round. Big Bass Splash raises its multiplier to 2x, 3x and then 10x as fishermen are collected.

Bonus choice. The player picks between modes after the trigger, as in The Dog House Megaways 1000's sticky or random wilds.

Wheel feature. A wheel decides the bonus or prize. Huff N' Even More Puff Grand has Wheel, Super Wheel and Ultra Wheel tiers.

Coin or hold feature. Special symbols lock in place while respins run, and each new coin resets the count. Pirots 5's Cursed Temple coin game plays on an 8x8 grid and resets to three respins whenever coins land.

Converted wins. A win is exchanged for a feature. Lucky Pharoah lets any win of 4x the bet or more be turned into Power Spins.

Upgrade feature. A symbol is permanently improved during the round. In Eye of Horus, each Horus wild in free games upgrades a picture symbol.

Optional stake modes

Ante bet. A higher stake per spin that raises the chance of triggering the bonus. Gates of Olympus 2500 has three ante levels. Names vary: Golden Winner's Fortune Bet, available in certain jurisdictions, raises the spin cost by 50% and uses stacked Bonus scatters to make free spins more likely.

Super spins. Very expensive base spins with guaranteed modifiers, such as at least one multiplier every spin. Sweet Bonanza 2500 offers two levels. Free spins cannot trigger in these modes.

Bonus buy or feature buy. Paying a fixed multiple of the stake to enter a bonus directly. Availability varies by jurisdiction; our bonus buy guide explains the details.

X-iter. ELK Studios' name for its range of purchase and boosted-stake modes, used in Pirots 5.

Gamble feature. An option to risk a win on a guess, such as a card colour. Some builds of Golden Winner and Eye of Horus list one, depending on jurisdiction.

Numbers printed in the information screen

RTP. Return to player, the long-run share of stakes a game is designed to return. See RTP and volatility explained.

Volatility. How unevenly the RTP is distributed between small, frequent results and rare, large ones.

Hit frequency. How often a spin returns anything. Sweet Bonanza 2500 lists about 1 in 2.33 spins.

Max win. The published cap on a single round, expressed as a multiple of the stake. Gates of Olympus 2500 caps at 25,000x.

Losses disguised as wins. A research term for returns smaller than the stake that are presented with win-style sounds or graphics. Dixon and colleagues found in 2010 that players reacted to them physiologically much as they did to real wins. The Gambling Commission banned this kind of celebration in UK-licensed online slots from October 2021.

Frequently asked questions

What is the difference between a wild and a scatter?

A wild substitutes for other symbols to complete wins. A scatter pays or triggers a feature wherever it lands and is usually not replaced by wilds.

Are sticky wilds and expanding wilds the same thing?

No. A sticky wild stays in place across spins; an expanding wild grows to fill its reel on the spin it lands.

Do multiplier wilds always multiply together?

No. Some games add values and some multiply them. The help screen says which, and the difference can be large.

What does "pay anywhere" mean?

Matching symbols count wherever they appear on the grid, usually eight or more, with no need for lines or adjacent reels.

Is an ante bet the same as a bonus buy?

No. An ante bet raises the cost of each spin to make the bonus more likely. A bonus buy pays a fixed amount to enter the bonus straight away.

Where can I check how a feature works in a specific game?

In the game's information screen, and in the game review on its SlotsRanker page.

Sources