What Is a Slot?


A slot is a narrow opening, as in a keyway or the slit for a coin in a vending machine. It can also be a position in a group or sequence, as in “he was slotted in at the last minute.” The phrase is derived from the Latin word for gap or crack, and may refer to either a physical opening or a position in a schedule or series.

A casino slot is a machine with spinning reels that pay out credits when winning combinations appear on the screen. Usually, a player inserts cash or, in ticket-in, ticket-out machines, a barcoded paper ticket with a unique barcode in a designated slot on the machine’s face to activate it. A button or lever (physical or virtual) then spins the reels and stops them in a pattern that pays out credits according to the machine’s paytable. Many slots have multiple paylines, and the number of lines can vary from one to 1024. Most slots have a theme, and symbols and bonus features align with that theme.

The earliest slot machines were mechanical devices invented by Charles Fey in 1899, which paid out paper tickets with barcodes that were scanned by a machine on the top of the machine. Later, electronic machines were developed that used a central computer to track the flow of transactions and process payments. These were known as central processor units (CPUs). Today’s digital machines use random-number generators (RNG) to determine the outcome of each spin and a paytable to show how much players can win.

In football, a slot receiver is the wide receiver closest to the line of scrimmage on running plays and the center of the field on passing plays. These players often face a higher risk of injury because they are in closer proximity to the defense than other wide receivers. They run routes that correspond with other receivers and are responsible for blocking the defensive line to protect the ball carrier.

In aviation, an airport slot is a time or place authorized by an air-traffic controller at an airport for the takeoff or landing of an aircraft. Air traffic controllers are responsible for assigning slots to airlines on a seasonal basis, and they must balance the demand for slots with the amount of runway and parking space available. As a result, some of the most sought-after slots are awarded to airlines that have been able to prove they can operate during peak times at the congested airports. These premium slots can be sold at a high price, such as the $75 million that Oman Air paid for a takeoff slot at Heathrow in 2016. The term can also refer to an operational area within an airline’s network. These areas are typically allocated by Eurocontrol, and are often called an execution pipeline or a functional unit. See the article on operation issue system for more information on these terms.