A slit or narrow opening, especially one for receiving something, as coins or letters. The term is also used of a position in a group, series, or sequence. (Origin uncertain.) Also: (Computers) A space in a circuit board where an expansion card can be inserted. A slot on a motherboard can be occupied by an ISA or PCI card, a memory chip, or a graphics card. (Dictionary of Computing)
From the classic mechanical designs that dominated casino floors to today’s towering video screens and quirky themes, slot machines have evolved in all sorts of ways. But the principles behind them remain the same. Whether you play at the strip or online, you need to understand how these eye-catching contraptions work before you spend any money on them.
To win, you must match certain symbols on a pay line—a line running through the center of the viewing window. Usually, you win if all of the reels display winning pictures along the pay line, but certain single images are also winners. The amount you win depends on which symbols land along the line, and the payout is the number of coins or tokens you receive for matching those symbols.