Slot Machine Features & Useful Terms

It’s rare to find an online slot nowadays that doesn’t offer at least a couple of bonus features. You can find bonus rounds, free spins, wilds symbols of many kinds, multipliers and much, much more! 

On this page we’re gonna have a closer look at each of these features and learn how they work. We’re also gonna look at the most common terms in the online gambling world and see what they all mean. Let’s get started!


Most commonly found in video slots, bonus rounds usually consist of some extra rounds or mini-games (like a pick-me game, for instance) that are part of the base game..They can be unlocked randomly or by triggering different combinations of symbols. 

Bonus rounds don’t only boost your chances of winning big prizes, but they also add to the entertainment value of the game. Bonus games can prove to be more fun and sometimes even more challenging than the base game, which encourages players to try to trigger them more often.


Spins are the engine, the core mechanism of any slot machine. But every spin comes with a small price. This is why free spins are one of the most popular features present in slots - they offer more chances to win, free of charge!

They can usually be triggered, just like bonus rounds, through a combination of symbols. The most common combinations are made up of scatter symbols. A slot can offer a large number of free spins, depending on its mechanics. 


Scatters are special symbols that usually register as some of the highest paying symbols on the reels. They may not appear often, but that’s partly what makes them so special. These symbols are usually designed in a way that reflects the slot’s design. 

Scatter symbols don’t have to appear next to one another to trigger a game event, like free spins or a bonus game. That’s actually where they get their name from, since they can help you win even while scattered. 


Most slots on the market today count wild symbols among their bonus features. The reason for this is that this feature has become hugely popular and has led to the emergence of many types of wilds, such as sticky wilds, expanding wilds and walking wilds just to name a few. 

Wilds are special symbols that can substitute for almost any other symbol on the reels, except for the scatter, much like a blank piece in a game of Scrabble. This helps players complete combinations that would otherwise be unobtainable and unlock huge rewards.


There are many types of wilds out there. Expanding wilds are, as their name suggests, wilds that expand outside of the initial location, covering a reel from top to bottom. They make every symbol on the reel wild, which can trigger huge wins. Expanding wilds can become active once they land on a highlighted reel. 


Stacked wilds are very common and easy to spot in slot games. They are similar to expanding wilds, with an important distinction: a single wild symbol falls on a reel and expands to fill in the space around it. They can expand to cover the whole reel or just the top or bottom sections. Stacked wilds are very frequently found in high volatility slots. 


Shifting wilds work by shifting one position in any direction on the reels. More often than not, they appear on the last reel and they can help complete combinations that would otherwise not be possible. In some situations, you may even be able to choose the location where the shifting wilds move to. 


Wilds are precious symbols, so it makes sense that we would want them to stick around - pun intended. That’s why we have sticky wilds, which stay glued to the reels for several spins, usually during an entire free spins sequence. Sure enough, this leads to many winning combinations being formed. 


Transferring wilds function in an interesting and instantly recognizable way. In most cases, a slot game with this type of wilds will feature an enlarged first set of reels. If any wilds happen to appear on that set of reels, they will transfer (or replicate) to the remaining reels, which means that you will have more chances to strike some winning combinations. 


Walking (or moving) wilds are a great addition to any slot game. As their name suggests, they move further and further away from their original location every time you spin the reels. If you’re really lucky, you might end up with a bunch of walking wilds roaming on the reels, helping you win some sweet rewards. 


This type of wilds don’t seem to be following any rules, but actually there are a handful of situations where you might have a better chance of finding them. Random wilds sometimes act like normal wilds or appear during bonus rounds and may also bring multipliers into the mix. It all comes down to the slot game you’ve chosen to play.


Multipliers are special symbols that are designed to - you guessed it - multiply your winnings. Some of them might do so in a moderate way, by just doubling or tripling your wins, while others can multiply by up to 1000x. Multiplier symbols typically appear during bonus rounds. 


As you can tell by their name, split symbols represent a single symbol that is split between two or more spots on the reels. They generally occur in 5x3 slots, but they make their way to other layouts too. As expected, split symbols increase your chance to complete winning combinations. Split symbols can be regular icons, Wilds or Scatters.


Progressive slots are some of the most thrilling slots you can play. Why? Because every time you spin the reels, you have a change to win the jackpot. The more you play, the more the jackpot grows. The adrenaline rush is real when you’re playing these slots, which is why there’s a popular choice amongst online gamblers.


Letting the reels spin by themselves for a little while is an awesome innovation for online slots. Most slot machines offer the option of autoplay and it can come in handy when you have to be away from the computer or your phone for a few minutes or you just want to take a break. You can just adjust the number of auto-spins you want and you’re all set! 


The hold feature is not very common in video slots, which makes it even more special. As opposed to most other features that operate on chance alone, the hold feature requires a certain amount of planning. Essentially, you get to hold (or freeze in place) a reel so that it doesn’t move when you hit spin. If done right, this can open up many winning opportunities. 


Nudges go hand in hand with holds, meaning that if a slot offers one of these features, there’s a chance it will also offer the other. Much in the same way as the hold feature, the nudge works by giving you the option to move one reel by one position. If you make a strategic move, you might end up with a winning combination on your hands.


Slots with colossal reels are easy to spot, they usually come in a large format with two sets of reels (a normal 5x4 and a 5x12 Colossal Reels set). Outside of their appearance, what’s special about them is that they automatically come with transferring wilds. Playing slots with colossal reels is a good way to collect some huge prizes, since more reels equals more chances for winning combinations.


Cascading Reels is a popular slot feature which is easy to grasp if you associate it with the game of Tetris. When you complete a combination, the winning icons disappear and new symbols replace the old ones. This innovative feature can generate huge winnings, and make standard symbols stand out more than usual. 


Waiting around for symbols to align and winning combinations to be formed can be downright frustrating. Luckily, some slots include what is called the rotating reels feature. This feature is usually part of some bonus round, and it works like so: after a standard spin and payout, the screen will start to rotate 90 degrees and a second payout will ensue. 

The same process repeats 3 more times, until the reels return to their original position, and by the end of it, you are paid out 4 times. Rotation reels therefore have the potential to boost your rewards substantially. 


This exciting feature can be manually activated by the player or be part of a bonus round, depending on the slot’s design. Win both ways essentially means that a payline can pay out in both directions, both left to right and right to left. That is bound to generate more rewards for you, so if you like that, then look for slots that include this feature.


The gamble feature is not included in all slot machines, but you should definitely give it a shot whenever you can find it. This feature gives you the option to gamble your winnings, for a 50/50 chance that you will double them. The gamble feature is usually part of a bonus round or an extra game where you have to make a guess or pick between two elements. 


With every spin, you have a chance to either form a winning combination or not. But many times, you get a near miss - meaning that if one single symbol would’ve been in a different spot, you would’ve won. With reel respins, you get a second chance - you can opt to spin one reel in order to try your luck again. The only downside is that respins come at a cost. 


You might have heard about low, medium or high volatility slots and wondered what that is. Volatility essentially refers to a slot’s risk factor, or how often and how much you can win at a slot machine. Low volatility means you can expect frequent small wins, while high volatility means that your wins will be larger but less frequent.


In any situation, it’s best to understand the basics before you move on to anything else and reels are probably the most basic component of any slot game. They represent the vertical positions of the grid, which move when you initiate a spin. The outcome of this spin is randomly generated. If you wish to learn more, we have an in-depth blog article on Slot Reels where we explain everything.


Paylines are another basic element of slot machines and a very common term you might come across when playing. They are essentially a static pattern that the game is programmed to recognize as correct, in other words, a winning combination. Modern slots typically have between 1 and 50 paylines, some even more. Check our guide on Slot Paylines to find out more. 


Paytables are a very useful way to get to know your favorite slot. Instead of playing blindly, without knowing what a slot has to offer, you can check out its paytable. There you’ll find plenty of information about all its symbols and their values, as well as details about its special symbols such as wilds and scatters, depending on the case. You can learn much more about slot paytables from our blog article All You Need To Know About The Slot Paytable.


Coins are essentially virtual currency used in online gambling. In most cases, the process is straightforward: you use this currency to wager with. Some developers, however, use coin values, which can confuse the player, because a big win like $1000 might seem like a lot, but it’s not really, if the value of a coin is set at $0.01. Our article on Online Slots Coins provides more information on this topic if you want to know. 


When a certain feature is retriggered in slots, it means that it can be repeated a number of times, as long as certain conditions are met. This term is usually associated with free spins rounds and it can, in some cases, continue indefinitely. Retriggering can help you score very large wins effortlessly.


RTP (or return-to-player) is the amount you can expect to win over a period of time playing a slot. If you invest $100 during a gaming session, a slot game with an RTP of 97% will most likely return $97 back to you. This percentage is predetermined, which means it’s programmed into the game by its developer.


Along with the reels, symbols are also the most basic elements in a slot game. Any slot on the market includes symbols. They are the colorful icons you find on the reels. There are low- and high-paying symbols, as well as special symbols such as the wilds and the scatters. Symbols usually also reflect the slot’s main theme. Check out our Complete Guide to Slot Symbols to learn more!


A slot’s theme has to do with the way the slot is designed in order to tell a particular story. The theme can sometimes be the most important aspect of the name, as it appeals easily to players’ interests. Some of the most popular slot themes are Las Vegas, Fruit Machines, Adventure and Sports.


With all this knowledge in mind, you are ready to play any online slot you lay your eyes on. You can now head over to our Free Slots page and choose your favorite slot game to play for free. Once you’ve mastered the basics and you want to take it to the next level, you can choose one (or many) of our Real Money Slots and start spinning those reels!