A slot is a thin opening into which something else can be fitted. The word is also used to refer to a specific position on something, such as in the case of a letter or postcard slot at the post office. The term is also used in computer hardware to describe a particular expansion slot. Examples include ISA, PCI, and AGP slots.
In modern casino slots, a random number generator (RNG) determines the sequence of symbols that appear on each reel. This sequence is then mapped to the appropriate stop locations on the reels by the computer. When the reels are spun, each location has a different probability of landing on a winning symbol.
The probability of a given symbol appearing on the payline can be calculated by dividing the total number of possible symbols in the machine by the number of symbols per reel. This method allows casinos to weight symbols on each reel, allowing for higher frequencies of certain symbols over others. It also allows for the appearance of long overdue jackpots, which are then paid out at a much faster rate than those that have accumulated over time.
A hot slot is a slot that pays out the most to players over a short period of time. These are often high volatility slots that pay out quickly but do not win very often. The reason for this is that they require a large amount of money to be played in order to be profitable.