This is a tie between a bettor and a bookmaker where the final score of a game or contest is exactly the same as the point spread, or the total points (combined scores of both teams).
In order to avoid a push, almost all betting lines include a half-point addition on all point spreads and point totals. This half-point addition is also known as a hook, and is what gives the house a distinct advantage over the bettor. For example, if the San Diego Padres are 3 run favorites vs. the Miami Marlins, the game would be listed as Padres -3 vs. Marlins +3. A push would occur if the Padres only win by 3 runs. A modern line would list: Padres -3.5 vs. Marlins +3.5, which avoids any possibility of a push. Most professional gamblers and avid sports bettors would prefer to avoid a push as well, since it means they make no money on the bet but still have to pay a small commission to their bookie.