In an age when players have a wide selection of games to play, attractive themes, designs and storylines are what keep them returning to slots. The industry’s major developers are continuously seeking to understand what makes a game “sticky” so that they can replicate those elements.

Until recently, most slot machines were 3-reel affairs that offered only basic animations and a handful of symbols on each reel. Today, the majority of online slots have multiple paylines and bonus features that add a lot to gameplay. Some of these features include a wild symbol, a jackpot or a free spins mode. Some of these games even offer a mini-game like placing oil rigs on a map in the Big Oil bonus round.

A slot is a narrow opening, notch or groove, especially one for receiving something, as a key in a lock, a coin in a machine or a position in a sequence or series. It may also refer to a vacancy or position, as in “a slot on the team” or “a spot at the table.”

In the past, slots were all-or-nothing affairs: You yanked the lever and either all the cherries or lucky 7s lined up and you won money, or you lost it all. Better computer technology allowed casinos to control the odds much more precisely and create more exciting, faster-paced games. Today, many slots have more than 100 possible paylines and can pay out payouts of up to 2000x your single line bet.