A slot is a narrow opening or groove in something, often used for receiving coins or paper tickets. It can also refer to a position in a game or activity, such as the starting point for players on a team.

A mechanical slot machine’s “candle” (or service lamp) is a small light on top of the machine that flashes to indicate a cash-in request, hand pay, a progressive jackpot win, or a technical problem. In modern video slots, this is usually a message displayed on the screen rather than a physical light.

The theoretical hold percentage is the expected return to a player over time, calculated using the machine’s paytable, reel strip settings, and coin denominations. It is determined by the manufacturer at the factory and cannot be changed after the machine is placed on the casino floor without reprogramming it.

Bonus features in slot games are extras that add to the enjoyment of playing the game. They can include free spins, mini-games, jackpots, multipliers, wild symbols, and scatters. Whether or not they are worth the extra investment depends on the individual player’s risk tolerance and preferences.

The paylines in a slot game determine what kind of prizes, bonuses, or features get triggered when the reels stop spinning. Some machines allow players to choose which paylines they want to bet on, while others have a fixed number of lines that can’t be altered. The former is referred to as a ‘free’ slot, while the latter is known as a ‘fixed’ slot.