“Against the spread” is a common sports betting term that refers to betting on whether a favorite or underdog will cover the point spread. The spread is calculated by oddsmakers. For example, let’s say in an NBA game between Boston and Miami, the spread is 3. Boston is the favorite at -3, which means in order to cover the spread, Boston must win by 4 or more. The Heat can either win outright or lose by 2 or fewer points to cover the spread.