A slot is a narrow notch, groove or opening, such as a keyway in a piece of machinery or the slit for a coin on a vending machine. It also refers to a position in a group, series or sequence. A car seat belt slots easily into place in the slot provided for it.
In a slot machine, the number of symbols available to form a pay line is limited by the number of reels and the fact that each symbol can only be present on one or more physical stops on the multiple reels. However, manufacturers have found ways to compensate for this limitation. For example, they weight the frequency of certain symbols to make their appearance on a pay line more disproportionate to their actual frequency on the displayed physical reel.
Almost nobody sits down at a slot and inserts $100, wins a large sum and then quits. This is because slot machines make their money from churn: players who keep playing, pressing the button like rats at a feeder bar, until their stake is gone.
There are a few situations where advantage plays exist on these machines, if the player is willing to expend the energy required to find them. It is important to understand how these plays work and to take care when trying them out, as the risk of losing too much can be high. Some enterprising individuals have figured out several different advantage play methods for these games, and many of them are freely shared online.