A special feature of the particular game theme, which is activated when certain symbols appear in a winning combination is called Bonus. The player is presented with several items on a screen from which to choose. A number of credits is revealed and awarded to the player when items are chosen. Some bonuses use a mechanical device, such as a spinning wheel. It is used in conjunction with the bonus for displaying the amount won.
There is a light on top of the slot machine called Candle. It flashes when change is needed and hand pay is requested.
The term carousel is used to denote a grouping of slot machines, usually in a circle or oval formation.
A container where the coins that are immediately available for payouts are held is coin hopper. It rotates coins into the coin tray when a player collects credits. A coin diverter is used to redirect excess coins into a drop bucket, or drop box when a certain preset coin capacity is reached.
Credit meter is used for displaying the amount of money or credits on the machine.
Drop bucket or Drop box is a container located in a slot machine's base where excess coins are diverted from the hopper. Typically, a drop bucket is used for low denomination slot machines. As for high denomination slot machines they use a drop box. A drop box contains a hinged lid with one or more locks whereas a drop bucket doesn't contain a lid. There exists a scheduled basis for collecting and counting the contents of drop buckets and drop boxes.
EMG is Electronic Gaming Machine.
To denote a payout made by a slot attendant or cage, rather than the slot machine the term Hand pay is used. A hand pay occurs when the amount of the payout exceeds the maximum amount that was preset by the slot machine's operator. At the level where the operator must begin to deduct taxes the maximum amount is set. A hand pay can also be a result of a short pay.
Hopper fill is a document used for recording the replenishments of the coin in the coin hopper after it becomes depleted as a result of making payouts to players. The slip indicates the amount of coins placed into the hoppers, the signatures of the employees involved in the transaction, the slot machine number and the location and the date.
Low Level or Slant Top slot machines are equipped with a stool for you to sit and play. Stand Up or Upright slot machines are played while standing.
Optimal play is a payback percentage based on a gambler using the optimal strategy in a skill-based slot machine game.
The term Payline is used to denote a straight or zigzagged line that crosses through one symbol on each reel, along which a winning combination is evaluated. There are up to nine pay lines in classic spinning reel machines while there can be one hundred pay lines in video slot machines.
While the meters count up to the amount that has been won the process of dramatizing a win by playing sounds happens which is called Rollup.
A partial payout made by a slot machine, which is less than the amount due to the player is called Short pay. It can happen if the coin hopper has been depleted as a result of making earlier payouts to players. The remaining amount due to the player is either paid as a hand pay or an attendant will come and re-fill the machine.
A document provided by the manufacturer for all slot machines is called Theoretical Hold Worksheet. It indicates the theoretical percentage that the slot machine should hold based on adequate levels of coin-in. The worksheet also indicates the reel strip settings, number of coins that may be played, the payout schedule, the number of reels and other information.
Weight count is an American term, referring to the dollar amount of coins or tokens removed from a slot machine's drop bucket or drop box and counted by the casino's hard count team through the use of a weigh scale.

You must know exactly the game you are playing.
Only the correct amount of money should be inserted into a machine. Always cash out your credits before leaving a machine.
Only if you have fun your gambling won't be stressful. You can increase your bets only when you are winning, and decrease your bets when you are losing.