Similar to betting the 2-way moneyline (without the draw), the Goal Line is a way for bettors to win a bet on multiple outcomes of the game. Goal Lines are similar to Puck Lines in hockey and Point Spreads in football or basketball... A Goal Line is typically 0.5 goals but for games with big favorites, the Goal Line may be 1,1.5, 2, 2.5, 3 and so on. A World Cup match between Argentina and Iran looks like this: 
Argentina -2.5 goals (2)
Iran +2.5 goals (4)
If you bet Argentina -2.5 goals, then to win the bet they must win by 3 goals or more. On the other side, betting Iran +2.5 goals means to win the bet, Iran can win, draw, or lose by 1 or 2 goals.
