A parlay bet is a wager that combines multiple individual bets into one single bet, where all selections must win for the overall bet to be successful. This type of betting allows for higher potential payouts since it multiplies the odds of each selected outcome, but it also comes with increased risk, as the failure of any single selection results in the entire parlay losing. In contrast, a single-game bet involves placing a wager on the outcome of just one specific event or game, allowing bettors to focus on a single matchup.