The 49ers spread refers to the point spread betting line associated with the San Francisco 49ers in NFL games. This spread indicates the margin by which the 49ers are favored or underdogs against their opponents. For example, if the 49ers are favored by 3 points, they must win by more than 3 for a bet on them to pay off. The spread is a popular betting tool, as it levels the playing field between teams of differing strengths, making games more competitive and engaging for bettors.