A slot is a narrow opening that you insert coins into to make a machine work. It can also be a keyway or slit on a piece of machinery, or in a vending machine, etc.
Until the 1990s — and even today in a few locations — players dropped coins into slots to activate games for each spin. However, this is no longer the case, with many live casinos now using bill validators and credit meters instead.
How a slot works
A player inserts money or a paper ticket with a barcode into a machine’s designated slot. Then, the machine is activated by a lever or button (either physical or on a touchscreen).
If symbols line up on the reels during a game’s rotation, the player earns credits based on the amount of money he bet before. The game’s paytable is usually displayed to the player before he starts.
In addition to a paytable, most slot machines have bonus features that can increase the number of winning combinations and payouts. These features can include random triggering of free spins, regular and wild multipliers, progressive multipliers, and more.
Video slot machines use computers to generate winning symbols on the reels. These computers weight the probability of each symbol appearing on the payline compared to the actual number of stops it occupied on the reels. This can make it seem as though a certain symbol has an incredibly high probability of appearing, when in fact the chances are much lower.