A slot is a place in a group or class. Slots are also used in a number of other applications, including naming, as in the name of an airplane or a ship, and for resource allocation. For example, when an airline buys capacity on a plane or at an airport, the airline is allocated slots that it can use to fly and land its aircraft.

In video slots, the symbols that line up when the reels stop are called paylines. They can be vertical, horizontal, diagonal, or zigzag and the number of them will determine how much a player wins, according to the pay table on the machine. The number of pay lines may vary from one machine to the next, and some have different types of symbols that activate unique bonuses or payouts.

Many slot machines have a theme. They can be themed after a city, movie, or other location. Others have themes that are more abstract, such as luck or fortune. Some slot machines have a progressive jackpot, which increases with each bet.

Some people claim to have developed strategies for winning at slot machines, such as moving on to another machine after a set period of time or after getting several good payouts (under the assumption that the machine will then tighten up). These strategies are useless because every spin is independent and random. The random number generator inside a slot does not take into account previous results.