Slots Terms and Glossary

A fixture at both brick-and-mortar and online casinos, slots remain possibly the most popular form of gaming out there. These colorful and exciting games have developed quite a following over the years, and like any cultural phenomenon that has been around for a while, the hobby has developed its own language. Though not as social as other casino games, would-be slot jockeys will want to know what it is their fellow gamers are talking about whenever they discuss their favorite titles.

Basic Terms

While you may be in a rush to learn some crazy phrases and sound like a pro, you’ll definitely want to get a grip on the essentials first. Concepts like the parts of the machine and the separate methods of winning are essential, and fortunately, quite simple to learn.

Coin Size:

In live-action play this literally denotes the size of the coin used to operate the slot machine. When playing online slots, however, it is used to signify the amount of the basic bet for the title you are playing.


A jackpot represents the largest amount of coins (or credits) you can win on a single spin.


A jackpot is the largest amount of money that a slots player can win on a given spin depending on both the machine they are playing and the bet size they are making. Some games offer ‘progressive’ jackpots, which accumulate over time and can be quite substantial.

Pay Line:

The set combinations of symbols that result in a payout for the player. Most machines and online slots have multiple pay lines

Pay Table:

Also known as a ‘pay schedule,’ a pay table is a small chart located on the machine that delineates every winning combination and the payout for each.

Random Number Generator (RNG):

An internal device in a slot machine that determines whether a spin is a winner or a loser. Through varied and complex mathematical calculations, the RNG activates a different sequence of numbers that are locked into place whenever a player makes their play. Modern RNGs typically run 24-7, and make unique calculations every few milliseconds. This design structure makes predicting a numerical pattern nearly impossible, and preserves the house edge on the machine.


The separate spinning wheels that showcase the strength of a player’s spin. Reels are covered in the symbols a player uses to judge whether or not they’ve won a spin, but are largely ornamental, as payouts are actually decided by the RNG. Live and online slot machines can have any number of reels, though most will have three or more.


Scatters help launch bonus rounds for extra winnings.


Much like wild symbols, scatters are unique images on the reels that can be used for a few different values. Scatters typically combine to launch bonus rounds of play or a unique jackpot.


The designs or markings located on the reels that show the player whether or not their spin is a winner. These are typically unique to individual games, and though they correspond with winning numerical combinations, they are technically only a visual interpretation of numbers set forth by the RNG.


Certain symbols like a cherry or character may be designated as wild.

Wild Symbols:

A unique symbol on the reels of certain slot machines that can equal any value on the RNG.

Slot Types:

While slot machines may seem like a relatively simple concept, developers have come up with several unique spins on the games over the years. Fortunately, their names are relatively clear, but to clear up any lingering uncertainty here is a collection of some of the many variations of the game:

  • Bonus Rounds:
  • These games offer players the chance for an extra payout in the event that the reels reveal a specific combination that will lead to a separate bonus round of gameplay or offer players additional “bonus” spins.
  • Flat-Top Slots:
  • Basic slot machines that do not offer bonus rounds and have a singular jackpot payout. Sometimes referred to as basic or “straight” slots.
  • Progressive Slots:
  • Progressive slots offer a special communal jackpot that is built up over time by taking percentages of plays made across multiple machines. These cumulative jackpots can grow quite large and are only available for players hitting a unique payline combination while playing with the maximum bet for the game.

Penny slots can have bets as low as 1 cent.

  • Penny Slots:
  • As the name may imply, penny slots allow players to make wagers as low as a single sent for one payline of the machine. While the minimum is static at 1 cent, the maximum bet varies wildly – meaning players can wager significantly more than a penny on these games should they desire.
  • Video Slots:
  • Digital slots that are typically more animated than average titles, often featuring many animations or direct video that accompanies certain spins. Many have cinematic tie-ins and special bonus rounds that coincide with the theme.

Advanced Terms

With the basics covered, there are a few more words and phrases that would be slots players should know before they start their spins.


A special format wherein different coins or bet values trigger specific symbol payouts, i.e. different symbols will be treated as jackpots or wilds depending on the coin size used to make the initial bet.


The amount of money the casino/house will withhold from its payouts to winners. Typically, players win between 94 and 96 percent, meaning the hold can be between 6 and 4 percent.

Loyalty Points:

Special bonus points that some online and live action casinos will offer regular players. These can typically be accumulated and exchanged for cash and prizes.


Multi-site progressive slots generate jackpot numbers from machines in multiple locations.

Multi-site Progressive:

A progressive slot wherein the jackpot draws from machines across more than one location simultaneously.

Optimal Play:

The ideal form of play for slots, a strategy that allows players to get the most profit from their play.

Rain on the Roof:

The sound of coins falling into the tray of a live-action slot machine; also colloquially used to describe winnings.


The lights, sounds and/or video that accompany a winning spin.

Stop Loss:

The threshold at which point a player decides to quit playing slots for the time being. This could be a monetary point or a time frame.

Win Rate:

The rate at which a slot machine pays out. Though the RNG prevents this rate from being too easily observed, looser slots with better pay schedules can be spotted over time.