A narrow notch or groove, as in the slot on a door for a lock. Also: A position or period of time that can be reserved for an event or activity, such as an open time slot on a calendar. See also: slot (disambiguation), and schedule.

Invented in the late 1800s, slot machines were first popular in bars and saloons across the United States. They used mechanical reels and a lever or button to activate them, but the outcome was determined by luck and probability rather than random number generation like today’s electronic machines.

In the modern world, slots are usually programmed to use a random number generator to ensure fairness and unpredictability. They can be played with coins or paper tickets with barcodes, or with virtual buttons on a touch screen. Regardless of how they’re triggered, most slot games feature themed symbols that align with the game’s overall design and structure.

The term jackpot grew from the more specific 19th-century meaning of “a hand that beats all others and establishes a new high standard for bidding.” Today, the word is commonly applied to any large, sudden, and unexpected windfall. Investors who buy shares in a hot initial public offering are often said to have hit the jackpot if the company’s stock price rises rapidly and dramatically, allowing them to cash out with substantial profits. It’s human nature to daydream about winning the lottery or backing the right horse, and those daydreams often involve what you could do with a big windfall.