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Online Slots: The Terms You Need to Know

First time playing online slots?

At PlayFrank Online Casino, we’ve got heaps of online casino slots for all kinds of players, and at any level of experience. What’s more, we’ve compiled a glossary of the most common slot terms, with an accompanying explanation below.

PlayFrank offers different kind of slots, from pub fruit machines to video slots, we’ve got a seperate guide all about slots.

Without further ado, here are some basic functionalities and mechanics related to online slots gameplay. Grab a cuppa and read it through.

5 reels online slot

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Slot term glossary index

Online slot terms explained


Reels are the spinning columns with the colourful symbols. Most online slots have 5 reels, though this number does vary. For example, you’ll see that a lot of classic slots can have 4 reels, 3 reels or even a single reel, while modern slot games can have 6, 7 or even more reels. Playing a 6-reel or 7-reel slot compared to a lower reel slot does not increase your chances of winning, mind you. 

Bet amounts

The bet amount is the money you spend on every spin. You can manually set this value by adjusting the coin value and coin level from the console of the online slot. The amount of money that you can bet with each spin can range widely in one single game, from just 0.10 cents a spin to a heart-racing £100. Some online slots have a feature which allow you to instantly increase the betting amount to ‘max bet’ if you’re feeling especially lucky right before a spin. With that in mind, always make sure that you gamble responsibly and can bet only as much as you can afford.


Also called win lines or bet lines, these are the vertical, horizontal or diagonal lines that pay out a sum of money when particular combinations of symbols fall along them. Most games pay from left to right, but some titles pay both ways. Players can usually set the number of active paylines on the reels and this determines the size of your bet, however some games have fixed paylines.


This is usually a screen shows a complete list of the payouts you can win when landing certain combinations of symbols. This amount is usually given as a multiple of your wager.


A spin is triggered after clicking the SPIN or PLAY button and sets the slot reels in motion. More interestingly, some games have an autoplay and autospin function that lets you spin the reels a predetermined number of times, or until you’ve spent a predetermined amount of money.

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Slot terms for more advanced players

So far, pretty simple, right? Well, let’s go deeper down the rabbit hole. Now that we’ve got the basics out of the way, let’s move on to some cooler features that are present in many of the more modern video slots. Keep your eyes peeled for these terms when you’re playing slot games; each feature offers you a different way to increase the size of your potential payout when you wager your next bet.


Wilds are symbols that substitute for any other symbol on a payline. These symbols increase your chances of a winning combination when they appear on the reels. There are different types of Wild symbols, including stacked wilds, random wilds, sticky wilds and moving wilds - each of them act in a slightly different way, but all are based on the concept of substituting other reel symbols.

Slot Wilds

Free spins

These are additional spins that are awarded to the player at no extra cost. These can be triggered randomly or by hitting special symbols on the reels. Retriggering free spins frequently is your ticket to a big win, especially if stacked wilds and multipliers are available. You’re basically having the reels spin for you at no cost to you whatsoever. Many online slots have ‘free spin’ symbols that can unlock a free spin bonus round. The number of free spins you’re awarded will depend on the game, and on which way you activated the free spins.


Multipliers boost your payout by the number (or multiplier level) that is currently active on the reels. Certain online slots award free spins with multipliers or sticky function multipliers. This feature increases the value of your bet without you having to wager anything extra.

Advanced autoplay

Advanced autoplay or autospin functions allows you to have the reels spin automatically until a predetermined number of spins have been reached, or until a predetermined amount of money has been bet on the spins. 

Honestly, these features are just the tip of the iceberg. Slot games are filled with unique bonuses, and if you’re interesting in learning about the most common, we suggest you check out our comprehensive Bonus Slots page.

Three common slot terms players mix up

We’ll wrap things up by covering some of the more obscure terminology used in online slots games. Still, if you’re curious what these words really mean, then read on to find out.

Hit frequency

This refers to the probability that an online slot machine will return a winning combination after a spin. It’s usually expressed as a percentage and this number determines which games are high and low hit frequency, with the former giving you a better chance of winning money over time.

Return to player (RTP) or payback rate

What is RTP? This is a term used by casinos to refer to the percentage of all wagered money that a slot will return to the players over time. Online slot machines have different payback rates depending on its features: the higher the RTP, the better the likelihood of winning back a bigger share of the money you wagered.


A slot game’s ‘volatility’ refers to how often, and how much, you are likely to win. High volatility slots tend to pay out a larger sum of money though infrequently, which means you could be waiting quite some time for a win (but the win is far more likely to be big). Low volatility slots, meanwhile, pay out smaller amounts on a relatively more consistent basis.

Top Online Slots UK Edition

You may have occasionally heard some online slots referred to as ‘UK slots’ or even ‘UK-friendly slots’. This simply means that those slots are accessible for a UK audience (as opposed to games available only in non-UK markets), but may also include slots that are particularly popular with British players. For example, Starburst and Cleopatra are hugely popular amongst online casino fans in the UK, so they might be described as UK slots.

famous british slots like Cleopatra

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PlayFrank is a UK Online Casino because we specialize in bringing the best online slots to our British audience. When you play online casino slots at PlayFrank, you can rest assured that you’re enjoying games which are trusted by, and localized for, UK players.

But our vast selection of UK slots isn’t the only reason PlayFrank should be your obvious choice of online casino as a UK player. We employ British slot reviewers and English-speaking 24/7 support agents

Simple yet immersive; there’s no doubt about it - slot games make for the ultimate ‘entertainment break’. Whether you want to experiment with online slots in free play mode (a demo game where you don’t have to pay) or dive straight into real money slots (where you can bet for the chance to win big cash prizes) - PlayFrank UK provides a fun and reliable online casino experience for British players.

Please note: British players are no longer able to play the free demo mode unless they register. Signing up at PlayFrank does not take more than a few minutes. 

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