In NBA betting, the spread (or point spread) is the predicted point difference between two teams. The favored team is assigned a negative number (e.g., -5.5), meaning they need to win by more than that number of points to 'cover the spread'. The underdog has a positive number (e.g., +5.5), and they can either win the game outright or lose by less than that number to cover the spread. Understanding the spread is fundamental for making informed NBA bets.