Parlay bets, also known as multi bets, accumulator bets, or combo bets in different regions, are a form of sports betting where multiple selections are combined into a single bet. The key feature of a parlay bet is that all the individual bets, known as "legs" of the parlay, must win for the parlay bet to pay out.

Here's a more detailed explanation:

Combining Multiple Selections: In a parlay bet, you combine multiple individual bets into one. These can be from the same sport or different sports, and they can involve different types of bets (e.g., moneyline, point spread, totals).

Increased Potential Payouts: The odds for each selection are multiplied together to calculate the total odds for the parlay. This leads to higher potential payouts compared to placing each bet separately. However, this also comes with a higher risk since if even one selection loses, the entire parlay bet is lost.

All or Nothing: The "all or nothing" nature of parlays is what makes them particularly risky but also potentially very rewarding. It's a popular betting choice for bettors looking for big payouts from a small stake.