What does over-under mean?

Answer 1

Betting if the score is going to be over a set number of points, or under that set of points.

Example: Gamblers may set the New England/Indianapolis game at 45 points. This could be referred to as 'the over/under for the Patriots/Colts game is 45 points'. The bettor will then decide if the total points scored in the game will be more than 45 points or less than 45 points. If the bettor decides that less than 45 points will be scored, they will bet the 'under'. If the bettor decides that more than 45 points will be scored, they will bet the 'over'.