The word slot is used to describe a wide variety of machines, but all operate the same way: With a pull of a lever or push of a button, a number of reels containing symbols spin. If the symbols line up in a row on a payline, the player wins. Online slots work the same way, but instead of a lever or button you simply click on the screen to activate a spin.

There are several types of slot games, and each has its own rules and payout structure. Payout tables will inform you of how much you can win on a single spin, and what symbols are required to trigger different bonuses or features such as free spins or extra cash. You should also familiarize yourself with the different pay lines, as these will determine how often you can hit a winning combination.

In the past, players dropped coins into slot machines to activate a spin, but this changed when bill validators and credit meters were added. These machines allow players to advance credits with a swipe of a card, and the difference between cash and play money is often blurred in online casinos.