A push in point spreads means that the two teams hit the spread exactly. So in the Duke vs Syracuse example, if the final score of that game was Duke winning 70 - 60 the exact difference there is 10 points and that was the point spread. In this case, you get back the money you bet, with no profit, but also no loss. This is why you will see odds like -10.5 because that extra .5 points removes the possibility of a push.