A slot is a dynamic placeholder that either waits passively for content (passive slots) or actively calls out to the renderer to fill it with content (active slots). Slots work in tandem with scenarios and renderers.

A slot’s name is typically related to its theme. The most common themes are Egyptian, Fruit, Romance and Movie-inspired. Most slots have symbols that match the theme and each machine has a pay table that lists how many credits the player will earn if a particular combination of symbols lines up on the machine’s pay line.

Modern slot machines are, at heart, a computer running millions or billions of numbers per second. When you press the spin button, you are merely stopping the RNG at that moment. The music, mini-games and actual appearance of spinning reels are just window dressing to keep you engaged.

In the early days of electromechanical slots, manufacturers used to make their machines appear more like random number generators by modifying the odds-calculator so that the probability of a winning symbol appearing on each reel was disproportionately high. This was referred to as a “taste” and it caused players to keep gambling in spite of the fact that they had lost more money than they had won.

With the advent of microprocessors, manufacturers were able to alter the odds-calculator again, this time by weighting particular symbols on each reel. This made the appearance of a jackpot symbol seem much closer than it actually was. This was a major source of frustration to slot players who could not understand why they were so close to hitting the big prize and it is this that gave rise to the term, “The Tilt.”